Conservapedia - User contributions [en]

United States of America

2018-12-23T22:55:07Z

Ihatehumans: Add some truth

{{Country
|name =''United States of America''
|map =US map.PNG
|map2 =Loc of United States.png
|established=1776
|flag =50 star flag.png
|arms =United States arms.png
|capital =Washington, D.C.
|government =Constitutional Republic
|language =English
|official =n
|president =Donald John Trump
|area =3,796,742 sq mi
|pop =325,719,178 (2017)
|gdp =$19.390 trillion (2017)
|gdp-year =
|gdp-pc =$59,501 (2017)
|currency =United States Dollar (USD)
}}
The '''United States of America'''<ref>(''conventional short form'': '''United States'''; ''abbreviation'': '''US''' or '''USA'''; sometimes also referred to as '''the States''' or simply as '''America''')</ref> is a [[federal republic]]<ref name="NotDemocracy">Multiple references:
*Snowball, Timothy (October 29, 2018). [https://thehill.com/opinion/campaign/413142-the-united-states-is-not-a-democracy-and-it-wasnt-meant-to-be-one The United States is not a democracy — and it wasn't meant to be one]. ''The Hill''. Retrieved October 29, 2018.
*Humphrey, Clifford (February 7, 2018). [http://thefederalist.com/2018/02/07/sorry-liberals-america-not-democracy-better-way/ Sorry, Liberals, But America Is Not A Democracy, And It’s Better That Way]. ''The Federalist''. Retrieved December 13, 2018.
*Williams, Walter E. (January 16, 2018). [https://www.cnsnews.com/commentary/walter-e-williams/us-not-democracy The US Is Not a Democracy]. ''CNS News''. Retrieved December 13, 2018.</ref> of fifty states, a capitol district, and fifteen territories. It is a prosperous, self-centered and relatively [[conservative]] and Christian nation, based on the longest-running [[Constitution]] in history. Located on the [[North American]] continent, it is bound mainly by [[Canada]] to the north, [[Mexico]] to the south, the [[Pacific Ocean]] to the west, and the [[Atlantic Ocean]] to the east. Founded originally as 13 colonies in the [[British Empire]], Britain's American colonies formally broke with the mother country on July 4, 1776, with the [[Declaration of Independence]].<ref>IN CONGRESS, JULY 4, 1776. [http://www.ushistory.org/Declaration/document/index.htm The unanimous Declaration of the thirteen united States of America], ushistory.org, (Accessed August 2010).</ref> Britain formally recognized the independence of the new nation, the United States of America, in the 1783 Treaty of Paris, which ended the [[American Revolutionary War]]. Shortly thereafter, in 1787, the [[United States Constitution]] was written; grounded on [[Republican form of government|republican]] political principles.

The Constitution remains in effect today, albeit with several amendments since then. The Americans created political parties and, since abolishing [[slavery]] in a bloody [[American Civil War|civil war]] (1861–65), instituted a form of government guided by the rule of law rather than the desires of a majority of voters. According to the U.S. Constitution written by America's [[Founding Fathers]], the United States is a [[Constitutional Republic]] that functions as a representative [[democracy]]. America derives many of its policies from Christian Principles and the logic behind the Bible(See the section on ''Natural Law''). Many people view America as holding a special place among nations, due to its foundations in liberty and justice.

America's [[free market]] economy grew rapidly, becoming the largest in the world by the 1870s. Between 1791 and 1959, 37 new states were added to the original 13 as the nation expanded across the North American continent and acquired a number of overseas possessions. After defeating the Soviet Union in the [[Cold War]], the U.S. emerged as the world's only [[superpower]], having the largest economy and most powerful military. It exerts enormous cultural and intellectual influence worldwide, and in return is the target of the enemies of democracy and [[capitalism]].

The capital of the United States of America is [[Washington, DC]].

== People ==
[[File:Php3sfokfPM.jpg|225px|left|At Washington, DC.]]
Population: 321,634,000 (2015 est.)<ref>2016 ''Britannica Book of the Year''.</ref>
Population growth rate: 0.97% (2010 est.) Labor force: 153.9 million (2010 est.).

Ethnic groups: white 79.96%, black 12.85%, Asian 4.43%, Amerindian and Alaska native 0.97%, native Hawaiian and other Pacific Islander 0.18%, two or more races 1.61% (July 2007 estimate) note: a separate listing for Hispanic is not included because the US Census Bureau considers Hispanic to mean persons of Spanish/Hispanic/Latino origin including those of Mexican, Cuban, Puerto Rican, Dominican Republic, Spanish, and Central or South American origin living in the US who may be of any race or ethnic group (white, black, Asian, etc.); about 15.1% of the total US population is Hispanic <ref>[https://www.cia.gov/library/publications/the-world-factbook/geos/us.html CIA - The World Factbook.]</ref>

In 2010, around 400,000 [[illegal immigrants]] were deported. The Pew Hispanic Center, a nonpartisan research organization in Washington, estimates 11.5 million to 12 million "unauthorized migrants" live in the US today.<ref>[http://www.csmonitor.com/2006/0516/p01s02-ussc.html Illegal immigrants in the US: How many are there?]</ref>

Although the diverse group of immigrants that have come to the U.S. speak many languages, [[English]] is the traditional unifying language of the United States and is necessary for full civic and cultural participation.

The religious affiliation of the United States is summarized in the following table.<ref>2016 ''Britannica Book of the Year''.</ref>
{| class="wikitable sortable"
|-
!Religion
!Percentage
|-
|Independent Christian
|23.2%
|-
|[[Roman Catholic]]
|19.6%
|-
|[[Protestant]] (including Anglican)
|18.9%
|-
|unaffiliated [[Christian]]
|16.5%
|-
|[[Mormon]]/[[Jehovah's Witnesses]]
|3.3%
|-
|Jewish
|1.9%
|-
|Orthodox
|1.8%
|-
|Muslim
|1.6%
|-
|Buddhist
|0.9%
|-
|Other
|12.3%
|}

==Geography==

[[File:Colorado.jpg|thumb|[[Colorado]].]]
Forty-eight of the fifty United States form a regional grouping known as the contiguous United States, bordering both the North [[Atlantic Ocean]] and the North [[Pacific Ocean]] and lying between [[Canada]] and [[Mexico]]. Two of the fifty states, Alaska and Hawaii, are not contiguous with any of the other states. Alaska is located to the northwest of [[Canada]] and lies across the [[Bering Strait]] from the Russian Federation. [[Hawaii]] is an [[archipelago]] located in the North Pacific Ocean. Puerto Rico, which is largely self-governing, is a commonwealth and is considered part of the U.S., as are several smaller territories in the Pacific Ocean, such as Guam. Each of the 50 states has a large degree of sovereignty, but the boundaries are debated and shift slightly every year.

At over 3.7 million square miles (over 9.6 million km²), the U.S. (including its non-contiguous and overseas states and territories) is the third largest country by total area (after Russia and Canada). It is the world's third most populous nation, with over 350 million people (after China and India).

Mt. McKinley, Alaska, is the highest point in North America and Death Valley, California, is the lowest point on the continent.<ref>[https://www.cia.gov/library/publications/the-world-factbook/geos/us.html CIA World Factbook], ''North America :: United States'', Updated on February 23, 2011, (Accessed on February 23, 2011).</ref>

Most American cities, such as [[Los Angeles]] or [[New York City]], are ugly, partly due to the massive inner-city crime within their boundaries and their failed leftist leadership which has ruined quality of life.

==History==
===Natural Law===
Many people familiar with the American Revolution do not realize that America is based on [[Natural Law]]. As [[Cleon Skousen]] points out:
{{cquote|Most modern Americans have never studied Natural Law. They are therefore mystified by the constant reference to Natural Law by the Founding Fathers.<ref>{{cite book|last1=Skousen|first1=Cleon|title=[[The Five Thousand Year Leap]]|date=1981|pages=33}}</ref>}}
[[Natural Law]] recognizes that certain laws are natural; that is, these laws naturally existing ''pre-date'' the existence of governments. Natural Law[s] generally indicate the existence of natural rights as well, which [[John Locke]] writes about in his book [[Two Treatises of Government]]. The writings of John Locke are mentioned several times in both the [[Constitutional Convention]] as well as [[The Federalist Papers]]. Natural Law is not only something that was very well understood by the generation that would become the [[Founding Fathers]], but it was also well recognized by the generations preceding the founding generation. Those generations that landed on the shores of America, most of whom were seeking religious liberty. The relationship between Liberty, Natural Law, and God can be seen in many of the documents preceding the founding, such as the dedication given at the [[Liberty Tree]] by a [[Sons of Liberty|son of liberty]] named [[Silas Downer]], as well as the first written constitution of the 13 colonies, [[Connecticut]]'s [[Fundamental Orders of Connecticut|Fundamental Orders]]
===American Revolution===
{{main|American Revolution}}
[[File:Washington-deleware.jpg|thumb|left|Washington, Chief of the Continental Army, is shown crossing the Delaware River.]]
The American Revolution exploded from fears the British Empire was trying to restrict the historic rights and liberties of Americans. The British victory in the French and Indian War ended the threat that foreign powers might attack the colonies; Britain's protection was no longer needed. At the same time, Britain decided to assert its powers by imposing [[taxes]]. The taxes (as on stamps, sugar, and tea) were not large but the principle was simple: Americans insisted their own [[legislature]]s could impose taxes but not [[Parliament]], because Americans were not represented there. "No taxation without representation!" and "[[Don't tread on me]]" became common phrases in America by the American people, but the British refused over and over again to accept it. London sent in troops when Boston protested vehemently, and Americans organized shadow governments in every colony.

The Americans were adopting a new political philosophy, called [[republicanism]], which stressed civic virtue, fear of corruption, and disdain for [[aristocracy]] (there were no aristocrats in America apart from occasional British visitors). Republicanism alerted Americans to their constitutional rights as Englishmen – one right was that the people, through their elected officials, set the taxes and upheld law. Constitutionally, to Americans their "elected officials" were not represented in the British Parliament, it meant having their own colonial legislatures. The British replied haughtily toward this desire from the Americans, going so far as to suggest America was "virtually represented" by the British Parliament in some way or form.

====Boston Tea Party====
{{main|Boston Tea Party}}

The British Parliaments idea of representation in America fueled their desire to increase taxes on the Americans. The tax on stamps in 1765 incited near rebellion, as the 13 separate colonies began meeting together and sharing their grievances. The stamp tax was repealed but others followed, especially the tax on tea. In response, Americans boycotted tea and merchants refused to order it, except in Boston. There, a well-organized group of patriots dumped the tea in the harbor, historically known as the [[Boston Tea Party]]. These events infuriated London, so they sent troops to North America and stripped [[Massachusetts]] of its self-government and suspended the historic rights the colonists were so proud of.

====Thirteen Colonies====
{{main|Thirteen Colonies}} [[Image:Pop1750.jpg|right|thumb|400px]]

The thirteen original colonies began organizing shadow governments, called "Committees of Correspondence," which prepared the Americans for the day "patriots" (or "Whigs," as they called themselves) could assume all functions of local government. That day came when the British sent troops from Boston to seize gunpowder in attempt to dismantle a potential revolt, and the American patriots gathered there to defend their liberty. These patriots were known as the American "Minute men," a well trained militia, and had planned for this day at Lexington and Concord. When the militia clashed with the elite British troops they soundly defeated them, prompting an historic backlash from Britain. The American Revolution had begun.

The thirteen colonies, organized as the "[[First Continental Congress]]," became a national government as the shadow governments in each colony took control and ousted all royal officials. Congress set up a [[Continental Army]] and gave command to an American hero and Virginia's leader, [[George Washington]]. George Washington took charge in Boston, and he forced the British to leave in the spring of 1776. All 13 colonies were at this point in control of the American Patriots, and they listened as [[Tom Paine]] explained ''Common Sense'' principles, proudly boasting of America's strength and its power as a new nation. America, in its own right as an individual nation no longer needed nor wanted a foreign [[King]]. Congress called on the colonies to become States and to write new State constitutions. On July 4, 1776, Congress unanimously declared the independence of a new nation, the United States of America.

====France in the American Revolutionary War====
[[File:Marquis de Lafayette.jpg|thumb|[[Marquis de Lafayette]].]]
King [[George III]] could not abide the insolent Americans and he sent his small army and large navy to America in attempt to reconquer his lost colonies. They were able to recapture [[New York City]], but the King's failure to spread elsewhere greatly outweighed this small victory. The powerful Royal navy gave the British command of the seas and the ability to land troops anywhere and capture any specific place, but the shortage of British soldiers, and the very long 3000 mile supply line, meant that the British could only hold a few points at any one time. Hiring German soldiers (Hessians) was necessary, but they were not enough, for the Patriots always had more available soldiers. The British expectations that Loyalist would rise up and overthrow the Patriots was a [[chimera]]; the Loyalists did provide some help to British invasion forces, but were never strong enough to operate on their own or control any territory.

[[France]], humiliated by Britain in the 1760s, was stronger in the late 1770s than it was a decade earlier and wanted revenge against the British for their past woes. Thus, the French secretly armed and financed the Americans. Lafayette, a French general in the American Revolutionary War, served in the Continental Army under George Washington. He convinced France to send their first naval and land forces to the Americas and participated in defending Richmond, Virginia from Benedict Arnold and in the battle of Yorktown, Virginia; Lafayette contributed in no slight degree toward the grand result.

In 1777, the British sent a large army to invade [[New York]] and cut off the revolutionary states of [[New England]]. The plan was a disaster as the American militia captured the entire British invasion force at Saratoga. Encouraged by diplomat [[Benjamin Franklin]], the French recognized the United States as an independent nation, signed a treaty of alliance, and entered the war against Britain. Later, the treaty extended to [[Spain]] and the [[Netherlands]] as allies to America; Britain's diplomacy was disjointed that it had no allies at all, and was militarily matched or surpassed by America and its new allies. The British invasion of the South in 1780-81 was designed to bring out Loyalist support, but it failed and the second major British army was captured at the [[Battle of Yorktown]]. The British Parliament revolted at their reckless king and his incompetent government and sued for peace, which was achieved on terms favorable to the U.S. in 1783. About 20% of the Loyalists moved to [[Canada]], but many stayed in America, and the new peaceful nation resumed its rapid growth.

===New Nation===
[[File:Bierstadt Looking Down Yosemite-Valley 1865.jpg|thumb|[[Albert Bierstadt]], ''Looking Down Yosemite-Valley'', 1865.]]
In 1783, when the Treaty of Paris concluded the war of independence, the American population totalled some three million citizens and slaves living on about one million square miles of land. Tens of thousands of [[Native Americans]] also lived in the [[Northwest Territory]] and the Southwest.

The Thirteen original states are [[Connecticut]], [[Delaware]], [[Georgia]], [[Maryland]], [[Massachusetts]] (including [[maine]]), [[New Hampshire]], [[New Jersey]], [[New York]], [[North Carolina]], [[Pennsylvania]], [[Rhode Island]], [[South Carolina]] and [[Virginia]]. In 1790, an agreement between supporters of Jefferson and those of [[Alexander Hamilton]] resulted in the creation of the [[District of Columbia]] from part of [[Maryland]]; it has served as the national capital since 1800. The remainder of the 1783 territory was eventually organized as the states of [[Ohio]], [[Indiana]], [[Michigan]], [[Illinois]], [[Wisconsin]], [[Kentucky]], [[Tennessee]], [[Mississippi]] and [[Alabama]].

===Westward Expansion===
[[File:U.S. Territorial Acquisitions PD WC.jpg|thumb|left|Territorial acquisitions such as the Thirteen Colonies, the Louisiana Purchase, and British and Spanish Cession.]]
In 1803, [[French]] first consul [[Napoleon Bonaparte]] took advantage of a lull in his war with Great Britain to sell the [[Louisiana Territory]] to the United States, more than doubling the nation's land area. This territory would later be organized as the states of [[Minnesota]], [[North Dakota]], [[South Dakota]], [[Montana]], [[Wyoming]], [[Nebraska]], [[Iowa]], [[Missouri]], [[Arkansas]], [[Kansas]], [[Oklahoma]], and [[Louisiana]] proper. President Jefferson commissioned [[Lewis and Clark]] to explore the new territory from 1802 to 1804.

The U.S. seized, then purchased [[Florida]] from Spain in 1819. [[Texas]] joined the United States in 1845 after winning its revolution against Mexico.
[[File:Map Leading Group by County US.jpg|thumb|Map Leading Group by County, 2000.]]
After victory the [[Mexican American War]] of 1846-48, the U.S. purchased via the [[Treaty of Guadalupe Hidalgo]] territory that became the states of [[California]], [[Nevada]], [[Utah]], [[Colorado]], [[New Mexico]] and [[Arizona]]. In 1846 the U.S. and Britain agreed that the 49th Parallel (degree of latitude) would serve as the boundary between the U. S. and [[British Columbia]] (now part of Canada). The American portion became the states of [[Washington]], [[Oregon]] and [[Idaho]].

===Civil War===
{{main|American Civil War}}
An issue that had been left unresolved at the [[Constitutional Convention]] was [[slavery]]. The South's largely agricultural economy depended on slave labor to work its cotton plantations. The North was more heavily industrialized, and slavery was outlawed in northern states. After a series of failed compromises, the South broke away to form the [[Confederate States of America]], following the election of President [[Abraham Lincoln]] of the new [[Republican Party]] in the election of 1860. Four long years of war ended in the spring of 1865 with the surrenders of Confederate generals [[Robert E. Lee]] at Appomattox, [[Virginia]] and [[Joseph E. Johnston]] at Durham, [[North Carolina]].

===America Acquires an Empire===

In 1867, the U.S. purchased [[Alaska]] from [[Russia]]. It became a state in 1959.

Hawaii became an independent republic in 1894 and voluntarily joined the U.S. in 1898, becoming a state in 1960.

As a result of the [[Spanish-American War]], the United States took control of the [[Philippines]] and annexed [[Puerto Rico]] and [[Guam]]. The Philippines became independent in 1946, after the U.S. reconquered the islands from Japan in World War II. [[Puerto Rico]] has occasionally held referendum that ratified its continuing unique "Commonwealth" status as part of the United States. The residents of Puerto Rico are U.S. citizens. Guam continues as a U.S. owned territory with full citizenship for its inhabitants. The people of Puerto Rico and Guam have a vote in presidential primaries and a voice, but not a vote, in Congress.

==The Constitution and Politics in the United States==

[[Image:76485685i79.jpg|right|thumb|300px|The drafting committee presenting the [[Declaration of Independence]] to the [[Continental Congress]], painted by John Trumbull 1817–1819.]]

Between 1776 and 1788, the United States was governed according to the [[Articles of Confederation]]. The Founding Fathers formally established the current structure of the United States by ratification of the [[U.S. Constitution]] in 1788. Since 1789, that constitution has been the basic governing document. America's Founding Fathers understood that a democracy is always in flux and given to “mob rule,”<ref>[[Michelle Malkin]]. [http://michellemalkin.com/2009/03/27/the-coming-g20-riots-the-spread-of-mob-rule/comment-page-1/ The coming G20 riots & the spread of mob rule], ''Michelle Malkin'', March 27, 2009.</ref> while a republic is fixed and stable, resting on “the Laws of Nature and of Nature’s God.” Because of the uncertainty of democracy, [[Benjamin Rush]] — a signer of the Declaration of Independence — wrote: “A simple democracy is one of the greatest of evils.”<ref>AWR Hawkins. [http://pajamasmedia.com/blog/america-a-republic-not-a-democracy/ America: A Republic, Not a Democracy], ''Pajamas Media'', September 03, 2009.</ref>

[[Sovereignty]] in America comes from the citizenry ([[self-governance]]), and the basic political values are called "[[republicanism]]," (not to be confused with the [[Republican Party]],) especially the commitment to civic virtue and civic duty, and opposition to corruption and aristocracy. Popular political parties emerged in the United States in the 1790s; currently the two major political parties are the [[Democratic Party]], and the [[Republican Party]]. Minor parties are of little importance overall but can be useful in pushing certain topics to the public eye.

States within the United States must have their own individual Constitutions as well, which usually adhere to that individual State's understanding of Natural Law, however, the supreme rule of the United States Constitution take precedence.<ref>[http://newmexico.heavensentgaming.com/lexicon/american-modern-culture/ American modern culture] on the [[New Mexico Cultural Encyclopedia, Lexicon, and News]]</ref>

Contrary to popular belief, especially among [[liberal]]s, the United States is not a [[democracy]] and was never intended to be one.<ref name="NotDemocracy"/>

=== The Role of Religion in Government ===
{{main|Religion and U.S. Government}}

==Government==
{{main|United States Federal Government}}

[[Image:56eugyjnm.jpg|right|thumb|300px|The [[White House]], the official home and workplace of the [[President of the United States]] of America.]]

===Executive Branch===

*Chief of state: The [[President of the United States]] is both the chief of state and head of government
*Head of government: President of the United States; [[Vice President of the United States]]
*Cabinet: Cabinet appointed by the president with Senate approval
*Elections: The president and vice president serve four-year terms (eligible for a second term)

===Legislative Branch===

The United States legislative branch of government is a [[bicameral]] Congress, which consists of the [[United States Senate|Senate]] (100 seats, 2 members are elected from each state by popular vote to serve six-year terms; one-third are elected every two years) and the [[House of Representatives]] (435 seats; members are directly elected by popular vote to serve two-year terms).

===Judicial Branch===
{{main|Supreme Court of the United States}}

The United States [[Supreme Court]] consists of nine justices, nominated by the president and confirmed with the advice and consent of the Senate. The judicial branch also includes the United States Circuit Courts of Appeal, and the United States District Courts. Article III, Section 1, of the U.S. Constitution provides that judges serve "during good Behavior," ''i.e.'', until they resign, die, or are impeached. The Supreme Court's decision in ''Marbury v. Madison'' established judicial review, whereby the federal courts have the power to declare federal and state laws and actions of the executive branch of the federal or a state government unconstitutional.

== Economy ==

The US has the largest and most technologically powerful economy in the world, with a per capita GDP of $47,400. In this market-oriented economy, private individuals and business firms make most of the decisions, and the federal and state governments buy needed goods and services predominantly in the private marketplace. US business firms enjoy greater flexibility than their counterparts in [[Europe]] and [[Japan]] in decisions to expand capital plant, to lay off surplus workers, and to develop new products. At the same time, they face higher barriers to enter their rivals' home markets than foreign firms face entering US markets. US firms are at or near the forefront in technological advances, especially in computers and in medical, aerospace, and military equipment; their advantage has narrowed since the end of World War II.

The onrush of technology largely explains the gradual development of a "two-tier labor market" in which those at the bottom lack the education and the professional/technical skills of those at the top and, more and more, fail to get comparable pay raises, health insurance coverage, and other benefits. Unfortunately, China remains both the banker and salesman to the United State's role as buyer, and debtor. This will not end well for the United States, Republican president or not. Since 1975, practically all the gains in household income have gone to the top 20% of households. The war in March–April 2003 between a US-led coalition and Iraq, and the subsequent occupation of Iraq, required major shifts in national resources to the military. Soaring oil prices between 2005 and the first half of 2008 threatened [[inflation]] and [[unemployment]], as higher gasoline prices ate into consumers' budgets. Imported oil accounts for about 60% of US consumption. Long-term problems include inadequate investment in economic infrastructure, rapidly rising medical and pension costs of an aging population, sizable [[trade deficit]]s and [[budget deficit]]s, and stagnation of family income in the lower economic groups.
[[File:Gast1872.jpg|thumb|"American Progress," painting by John Gast, 1872.]]
The merchandise trade deficit reached a record $840 billion in 2008 before shrinking to $506 billion in 2009, and ramping back up to $630 billion in 2010. The global economic downturn, the sub-prime mortgage crisis, investment bank failures, falling home prices, and tight credit pushed the United States into a [[recession]] by mid-2008. [[GDP]] contracted until the third quarter of 2009, making this the deepest and longest downturn since the [[Great Depression]]. To help stabilize financial markets, the US Congress established a $700 billion Troubled Asset Relief Program (TARP) in October 2008. The government used some of these funds to purchase equity in US banks and other industrial corporations, much of which had been returned to the government by early 2011.

In January 2009 the US Congress passed and President [[Barack Obama]] signed a bill providing an additional $787 billion fiscal stimulus to be used over 10 years - two-thirds on additional spending and one-third on tax cuts - to create jobs and to help the economy recover. Approximately two-thirds of these funds were injected into the economy by the end of 2010. In March 2010, President Obama signed a health insurance reform bill into law that will extend coverage to an additional 32 million American citizens by 2016, through private health insurance for the general population and Medicaid for the impoverished. In July 2010, the president signed the DODD-FRANK Wall Street Reform and Consumer Protection Act, a bill designed to promote financial stability by protecting consumers from financial abuses, ending taxpayer bailouts of financial firms, dealing with troubled banks that are "too big to fail," and improving accountability and transparency in the financial system - in particular, by requiring certain financial derivatives to be traded in markets that are subject to government regulation and oversight.

In November 2010, in an attempt to keep interest rates from rising and snuffing out the nascent recovery, the US Federal Reserve Bank (The Fed) announced that it would purchase $600 billion worth of US Government bonds by June 2011.

The United States is the leading industrial power in the world, highly diversified and technologically advanced; [[petroleum]], [[steel]], motor vehicles, aerospace, telecommunications, chemicals, [[electronics]], food processing, consumer goods, lumber, mining.
<ref>[https://www.cia.gov/library/publications/the-world-factbook/geos/us.html CIA - The world Factbook]</ref>

==Flag Description==
[[Image:50 star flag.png|left|thumb|150px|The [[Flag of the United States of America]]]]
{{main|Flag of the United States of America}}

Thirteen equal horizontal stripes of red (top and bottom) alternating with white; there is a blue rectangle in the upper hoist-side corner bearing 50 small, white, five-pointed stars arranged in nine offset horizontal rows of six stars (top and bottom) alternating with rows of five stars; the 50 stars represent the 50 states, the 13 stripes represent the 13 original colonies; known as Old Glory; the design and colors might have been the basis for a number of other flags, including [[Chile]], [[Liberia]], [[Malaysia]], and [[Puerto Rico]].

{{Clear}}

==References==
[[File:Weir, Afternoon by the Pond, ca. 1908-1909.jpg|thumb|Julian Alden Weir, Afternoon by the Pond, ca. 1908-1909.]]

{{reflist}}

{{Clear}}

== See also==
[[File:Lawrence The Migration of the Negro.jpg|thumb|The Migration of the Negro by [[Jacob Lawrence]], 1940-1941.]]
*[[Pledge of Allegiance]]
*[[Famous American artists]]
*[[List of 50 states]]
*[[Americas]]
*[[America (continent)]]
*[[Columbia]]
*[[Gallery of American Masterpieces]]
*[[Christian Nation]]
*[[American conservatism]]
*[[Sociology of "atheism is un-American" view]]
*[[Adair v. United States]]
*[[Americana]]

{{Clear}}

==External links==
*[[CIA]] - [https://www.cia.gov/library/publications/the-world-factbook/geos/us.html The World FactBook]
*[https://www.britannica.com/EBchecked/topic/616563/United-States United States.]
*[http://www.nationsonline.org/oneworld/america.htm America]
*[http://www.nationsonline.org/oneworld/flags_of_us_states.htm Flags of the U.S. States]
*[http://www.pibmug.com/files/map_test.swf Interactive map test of the 50 U.S. states]
*[http://www.u-s-history.com/pages/h445.html U.S. History]
*[http://www.theroot.com/buzz/who-owns-united-states Who Owns the United States?]
*[http://sociology.ucsc.edu/whorulesamerica/power/wealth.html Wealth, Income, and Power.] by G. William Domhoff, University of California Santa Cruz.
*[http://bertschlossberg.blogspot.com/ Real Life and Death: the Bible, Israel, and America interplay]

{{USstates}}

[[Category:North American Countries]]
[[Category:United States of America]]
[[Category:NATO Members]]
[[Category:United States History]]
[[Category:Featured articles]]
[[Category:Christian-Majority Countries]]

Haskell

2018-12-23T22:47:06Z

Ihatehumans:

'''Haskell''' {{IPAc-en|ˈ|h|æ|s|k|əl}}<ref>{{cite mailing list |url=http://www.haskell.org/pipermail/haskell-cafe/2008-January/038756.html |title=anybody can tell me the pronunciation of "haskell"? |date=28 January 2008 |accessdate=12 March 2011 |mailinglist=Haskell-cafe |last=Chevalier |first=Tim}}</ref> is a standardized, [[General-purpose programming language|general-purpose]], [[purely functional programming]] language with [[non-strict semantics]] and [[Strong typing|strong]] [[static typing]].{{sfn|Peyton Jones|2003}} It is named after [[logician]] [[Haskell Curry]].{{sfn|Hudak|Hughes|Peyton Jones|Wadler|2007}} The latest standard of Haskell is Haskell 2010. {{As of|2016|05}}, a group is working on the next version, Haskell 2020.<ref>https://mail.haskell.org/pipermail/haskell-prime/2016-April/004050.html</ref>

Haskell features a [[type system]] with [[type inference]]<ref>Type inference originally using [[Type inference#Hindley.E2.80.93Milner type inference algorithm|Hindley-Milner type inference]]</ref> and [[lazy evaluation]].<ref>This allows finer control over the expression [[evaluation strategy]]</ref> [[Type classes]] first appeared in the Haskell programming language.<ref>"Type classes, first proposed during the design of the Haskell programming language, ..." —[https://jgbm.github.io/pubs/morris-dissertation.pdf John Garrett Morris (2013), "Type Classes and Instance Chains: A Relational Approach" ]</ref> Its main implementation is the [[Glasgow Haskell Compiler]].

Haskell is based on the [[Semantics of programming languages|semantics]], but not the syntax, of the language [[Miranda (programming language)|Miranda]], which served to focus the efforts of the initial Haskell working group.<ref>Edward Kmett, [https://www.youtube.com/watch?v=hIZxTQP1ifo Edward Kmett - Type Classes vs. the World]</ref> Haskell is used widely in academia<ref>{{cite web|url=https://wiki.haskell.org/Haskell_in_education|title=Haskell in education|publisher=|accessdate=15 February 2016}}</ref><ref>{{cite web|url=https://wiki.haskell.org/Haskell_in_research|title=Haskell in research|publisher=|accessdate=15 February 2016}}</ref> and industry.<ref>{{cite web|url=https://wiki.haskell.org/Haskell_in_industry|title=Haskell in industry|publisher=|accessdate=15 February 2016}}</ref>

==History==
Following the release of [[Miranda (programming language)|Miranda]] by Research Software Ltd. in 1985, interest in [[Lazy evaluation|lazy functional languages]] grew. By 1987, more than a dozen [[non-strict]], purely functional programming languages existed. Miranda was the most widely used, but it was [[proprietary software]]. At the conference on [[Functional Programming Languages and Computer Architecture]] (FPCA '87) in [[Portland, Oregon]], there was a strong consensus that a committee be formed to define an [[open standard]] for such languages. The committee's purpose was to consolidate existing [[functional languages]] into a common one to serve as a basis for future research in functional-language design.{{sfn|Peyton Jones|2003|loc=Preface}}

===Haskell 1.0 to 1.4===

The first version of Haskell ("Haskell 1.0") was defined in 1990.{{sfn|Hudak|Hughes|Peyton Jones|Wadler|2007}} The committee's efforts resulted in a series of language definitions (1.0, 1.1, 1.2, 1.3, 1.4).

===Haskell 98===
In late 1997, the series culminated in ''Haskell 98'', intended to specify a stable, minimal, portable version of the language and an accompanying standard [[library (computer science)|library]] for teaching, and as a base for future extensions. The committee expressly welcomed creating extensions and variants of Haskell 98 via adding and incorporating experimental features.{{sfn|Peyton Jones|2003|loc=Preface}}

In February 1999, the Haskell 98 language standard was originally published as ''The Haskell 98 Report''.{{sfn|Peyton Jones|2003|loc=Preface}} In January 2003, a revised version was published as ''Haskell 98 Language and Libraries: The Revised Report''.{{sfn|Peyton Jones|2003}} The language continues to evolve rapidly, with the [[Glasgow Haskell Compiler]] (GHC) implementation representing the current ''de facto'' standard.<ref name=HaskellWikiImpl>{{cite web|title=Haskell Wiki: Implementations|url=http://www.haskell.org/haskellwiki/Implementations|accessdate=18 December 2012}}</ref>

===Haskell 2010===
In early 2006, the process of defining a successor to the Haskell 98 standard, informally named ''Haskell Prime'', began.<ref>{{cite web|url=https://prime.haskell.org/|title=Welcome to Haskell'|work=The Haskell' Wiki}}</ref> This was intended to be an ongoing incremental process to revise the language definition, producing a new revision up to once per year. The first revision, named '''Haskell 2010''', was announced in November 2009<ref name="2010ann"/> and published in July 2010.

Haskell 2010 is an incremental update to the language, mostly incorporating several well-used and uncontroversial features previously enabled via compiler-specific flags.
* Hierarchical module names. Module names are allowed to consist of dot-separated sequences of capitalised identifiers, rather than only one such identifier. This lets modules be named in a hierarchical manner (e.g., <code>Data.List</code> instead of <code>List</code>), although technically modules are still in a single monolithic namespace. This extension was specified in an addendum to Haskell 98 and was in practice universally used.
* The [[foreign function interface]] (FFI) allows bindings to other programming languages. Only bindings to [[C (programming language)|C]] are specified in the Report, but the design allows for other language bindings. To support this, data type declarations were permitted to contain no constructors, enabling robust nonce types for foreign data that could not be constructed in Haskell. This extension was also previously specified in an Addendum to the Haskell 98 Report and widely used.
* So-called ''n''+''k'' patterns (definitions of the form <code>fact (n+1) = (n+1) * fact n</code>) were no longer allowed. This [[syntactic sugar]] had misleading semantics, in which the code looked like it used the <code>(+)</code> operator, but in fact desugared to code using <code>(-)</code> and <code>(>=)</code>.
* The rules of [[type inference]] were relaxed to allow more programs to type check.
* Some [[Syntax (programming languages)|syntax]] issues (changes in the formal grammar) were fixed: pattern guards were added, allowing pattern matching within guards; resolution of [[Order of operations|operator fixity]] was specified in a simpler way that reflected actual practice; an edge case in the interaction of the language's [[lexical syntax]] of operators and comments was addressed; and the interaction of do-notation and if-then-else was tweaked to eliminate unexpected syntax errors.
* The <code>LANGUAGE</code> [[Directive (programming)|pragma]] was specified. By 2010 dozens of extensions to the language were in wide use, and GHC (among other compilers) provided the <code>LANGUAGE</code> pragma to specify individual extensions with a list of identifiers. Haskell 2010 compilers are required to support the <code>Haskell2010</code> extension, and are encouraged to support several others which correspond to extensions added in Haskell 2010.

==Features==
{{Main|Haskell features}}
{{See also|Glasgow Haskell Compiler#Extensions to Haskell}}

Haskell features [[lazy evaluation]], lambda expressions, [[pattern matching]], [[list comprehension]], [[type class]]es and [[type polymorphism]]. It is a [[purely functional language]], which means that functions generally have no [[Side effect (computer science)|side effects]]. A distinct construct exists to represent side effects, [[Orthogonal#Computer science|orthogonal]] to the type of functions. A pure function can return a side effect that is subsequently executed, modeling the [[Pure function#Impure functions|impure functions]] of other languages.

Haskell has a [[strongly typed programming language|strong]], [[static type#Static typing|static]] type system based on [[Hindley–Milner type inference]]. Its principal innovation in this area is type classes, originally conceived as a principled way to add [[Polymorphism (computer science)|overloading]] to the language,<ref name="wadler89">{{cite journal|last1=Wadler|first1=P.|first2=S. |last2=Blott|year=1989|title=How to make ad-hoc polymorphism less ad hoc|journal=Proceedings of the 16th ACM [[SIGPLAN]]-[[SIGACT]] [[Symposium on Principles of Programming Languages]]|publisher=[[Association for Computing Machinery|ACM]]|pages=60–76|doi=10.1145/75277.75283|isbn=0-89791-294-2}}</ref> but since finding many more uses.<ref name="hallgren01">{{cite journal|last=Hallgren|first=T.|date=January 2001|title=Fun with Functional Dependencies, or Types as Values in Static Computations in Haskell|journal=Proceedings of the Joint CS/CE Winter Meeting|location=Varberg, Sweden|url=http://www.cs.chalmers.se/~hallgren/Papers/wm01.html}}</ref>

The construct that represents side effects is an example of a [[Monad (functional programming)|monad]]. Monads are a general framework that can model different kinds of computation, including error handling, [[Nondeterministic algorithm|nondeterminism]], [[parsing]] and [[software transactional memory]]. Monads are defined as ordinary datatypes, but Haskell provides some [[syntactic sugar]] for their use.

Haskell has an open, published specification,{{sfn|Peyton Jones|2003}} and [[#Implementations|multiple implementations exist]]. Its main implementation, the [[Glasgow Haskell Compiler]] (GHC), is both an [[Interpreter (computing)|interpreter]] and [[Machine code|native-code]] [[compiler]] that runs on most platforms. GHC is noted for its rich type system incorporating recent innovations such as [[generalized algebraic data type]]s and type families. [[The Computer Language Benchmarks Game]] also highlights its high-performance implementation of [[Concurrency (computer science)|concurrency]] and [[Parallel computing|parallelism]].<ref name="shootout">[http://benchmarksgame.alioth.debian.org/u64q/haskell.html Computer Language Benchmarks Game]</ref>

An active, growing community exists around the language, and more than 5,400 third-party open-source libraries and tools are available in the online package repository ''Hackage''.<ref name="hackage-stats">{{cite web|url=http://hackage.haskell.org/cgi-bin/hackage-scripts/stats|archiveurl=https://web.archive.org/web/20130503114836/http://hackage.haskell.org/cgi-bin/hackage-scripts/stats|archivedate=2013-05-03 |title=HackageDB statistics |publisher=Hackage.haskell.org |accessdate=2013-06-26}}</ref>

==Code examples==
{{See also|Haskell features#Examples}}
A [[Hello world program|"Hello world" program]] in Haskell (only the last line is strictly necessary):
<source lang="haskell">
module Main (main) where -- not needed in interpreter, is the default in a module file

main :: IO () -- the compiler can infer this type definition
main = putStrLn "Hello, World!"
</source>

The [[factorial]] function in Haskell, defined in a few different ways:
<source lang="haskell">
-- Type annotation (optional, same for each implementation)
factorial :: (Integral a) => a -> a

-- Using recursion (with the "ifthenelse" expression)
factorial n = if n < 2
then 1
else n * factorial (n - 1)

-- Using recursion (with pattern matching)
factorial 0 = 1
factorial n = n * factorial (n - 1)

-- Using recursion (with guards)
factorial n
| n < 2 = 1
| otherwise = n * factorial (n - 1)

-- Using a list and the "product" function
factorial n = product [1..n]

-- Using fold (implements "product")
factorial n = foldl (*) 1 [1..n]

-- Point-free style
factorial = foldr (*) 1 . enumFromTo 1
</source>
Because the ''Integer'' type has [[arbitrary-precision]], this code will compute values such as <code>factorial 100000</code> (a 456,574-digit number), with no loss of precision.

An implementation of an algorithm similar to [[quick sort]] over lists, where the first element is taken as the pivot:
<source lang="haskell">
-- Type annotation (optional, same for each implementation)
quickSort :: Ord a => [a] -> [a]

-- Using list comprehensions
quickSort [] = [] -- The empty list is already sorted
quickSort (x:xs) = quickSort [a | a <- xs, a < x] -- Sort the left part of the list
++ [x] ++ -- Insert pivot between two sorted parts
quickSort [a | a <- xs, a >= x] -- Sort the right part of the list

-- Using filter
quickSort [] = []
quickSort (x:xs) = quickSort (filter (<x) xs)
++ [x] ++
quickSort (filter (>=x) xs)
</source>

==Implementations==

All listed implementations are distributed under [[open source license]]s.<ref name="implementations">[http://www.haskell.org/haskellwiki/Implementations "Implementations"] at the Haskell Wiki</ref>

Implementations that fully or nearly comply with the Haskell 98 standard, include:
* The ''[[Glasgow Haskell Compiler]]'' (GHC) compiles to native code on many different processor architectures, and to [[ANSI C]], via one of two [[intermediate language]]s: [[C--]], or in more recent versions, [[LLVM]] (formerly Low Level Virtual Machine) bitcode.<ref>{{cite web|
url=https://ghc.haskell.org/trac/ghc/wiki/Commentary/Compiler/Backends/LLVM|
title=The LLVM Backend|
website=GHC Trac}}</ref><ref>{{cite conference
| url = http://www.cse.unsw.edu.au/~chak/papers/TC10.html
| title = An LLVM Backend for GHC
| last1 = Terei
| first1 = David A.
| last2 = Chakravarty
| first2 = Manuel M. T.
| date = 2010
| publisher = ACM Press
| book-title = Proceedings of ACM SIGPLAN Haskell Symposium 2010}}</ref> GHC has become the ''de facto'' standard Haskell dialect.<ref>C. Ryder and S. Thompson (2005). [http://kar.kent.ac.uk/14237/1/Tech_Chris.pdf "Porting HaRe to the GHC API"]</ref> There are libraries (e.g., bindings to [[OpenGL]]) that work only with GHC. GHC is also distributed with the [[Haskell platform]].
* The ''Utrecht Haskell Compiler'' (UHC) is a Haskell implementation from [[Utrecht University]].<ref>[http://www.cs.uu.nl/wiki/UHC Utrecht Haskell Compiler]</ref> It supports almost all Haskell 98 features plus many experimental extensions. It is implemented using [[attribute grammar]]s and is currently used mostly for research on generated type systems and language extensions.
* ''Jhc'', a Haskell compiler written by John Meacham, emphasizes speed and efficiency of generated programs and exploring new program transformations.
** ''Ajhc'' is a fork of Jhc.
* ''LHC'' is a whole-program optimizing backend for GHC, based on Urban Boquist’s compiler intermediate language, GRIN.<ref>{{cite journal |last=Boquist |first=Urban |author2=Johnsson, Thomas |title=The GRIN Project: A Highly Optimising Back End for Lazy Functional Languages |journal=LNCS |year=1996 |volume=1268 |pages=58–84}}</ref> Older versions of LHC were based on Jhc rather than GHC.

Implementations no longer actively maintained include:
* The ''Haskell User's Gofer System'' ([[Hugs]]) is a [[bytecode]] interpreter. It was once one of the implementations used most widely, alongside the GHC compiler,{{sfn|Hudak|Hughes|Peyton Jones|Wadler|2007|p=12-22}} but has now been mostly replaced by GHCi. It also comes with a graphics library.
* ''nhc98'' is a bytecode compiler focusing on minimizing memory use.
** The ''York Haskell Compiler'' ([[Yhc]]) was a fork of nhc98, with the goals of being simpler, more portable and efficient, and integrating support for Hat, the Haskell tracer. It also had a [[JavaScript]] backend, allowing users to run Haskell programs in [[web browser]]s.
* ''HBC'' is an early implementation supporting Haskell 1.4. It was implemented by [[Lennart Augustsson]] in, and based on, [[Lazy ML]]. It has not been actively developed for some time.

Implementations not fully Haskell 98 compliant, and using a variant Haskell language, include:
* ''[[Gofer (software)|Gofer]]'' was an educational dialect of Haskell, with a feature called ''constructor classes'', developed by Mark Jones. It was supplanted by Hugs (see above).
* ''[[Helium (Haskell)|Helium]]'' is a newer dialect of Haskell. The focus is on making learning easier via clearer error messages. It currently lacks full support for type classes, rendering it incompatible with many Haskell programs.
*Eta and [[Frege (programming language)|Frege]] are dialects of Haskell targeting the [[Java virtual machine|Java Virtual Machine]].

==Applications==
* [[Darcs]] is a [[revision control system]] written in Haskell, with several innovative features, such as more precise control of patches to apply.
* [[Cabal (software)|Cabal]] is a tool for [[Build automation|building]] and packaging Haskell libraries and programs.<ref>{{cite web|url=https://www.haskell.org/cabal/|title=The Haskell Cabal|accessdate=8 April 2015}}</ref>
* [[Linspire]] GNU/Linux chose Haskell for system tools development.<ref>{{cite web|url=http://urchin.earth.li/pipermail/debian-haskell/2006-May/000169.html|title=Linspire/Freespire Core OS Team and Haskell|work=Debian Haskell mailing list|date=May 2006}}</ref>
* [[Xmonad]] is a [[window manager]] for the [[X Window System]], written fully in Haskell.<ref>xmonad.org</ref>
* [[Glasgow Haskell Compiler|GHC]] is also often a testbed for advanced functional programming features and optimizations in other programming languages.
* [[Pandoc]] is a tool to convert one markup format into another.
* The Shake build system, aiming to be reliable, robust, and fast.<ref>[http://shakebuild.com/ Shake Build System]</ref>
* ShellCheck - A shell script static analysis tool.<ref>[https://github.com/koalaman/shellcheck/ ShellCheck]</ref>

===Industry===
* [[Facebook]] implements its anti-spam programs<ref>{{cite web |title = Facebook’s New Spam-Killer Hints at the Future of Coding |url = https://www.wired.com/2015/09/facebooks-new-anti-spam-system-hints-future-coding/ |accessdate = September 1, 2015 |date = September 1, 2015 |website = [[Wired (magazine)|Wired]] |publisher = |last = Metz |first = Cade}}</ref> in Haskell, as [[open-source software]].<ref>[https://code.facebook.com/posts/302060973291128/open-sourcing-haxl-a-library-for-haskell/ Simon Marlow (2014), Open-sourcing Haxl]</ref>
* [[Swift Navigation]], a high precision GPS manufacturer, implements significant portions of its product in Haskell, providing some [[open source software]].<ref>[https://github.com/swift-nav/wolf/ Swift-Nav (2018)]</ref>
* [[Bluespec, Inc.|Bluespec]] SystemVerilog (BSV) is a language for semiconductor design that is an extension of Haskell. Also, Bluespec, Inc.'s tools are implemented in Haskell.
* [[Cryptol]], a language and toolchain for developing and verifying [[cryptography]] algorithms, is implemented in Haskell.
* [[seL4]], the first [[Formal methods|formally verified]] [[microkernel]],<ref name="klein-sosp09">
A formal proof of functional correctness was completed in 2009.
{{ cite conference
| first1 = Gerwin
| last1 = Klein
| first2 = Kevin
| last2 = Elphinstone
| first3 = Gernot
| last3 = Heiser
| author3-link = Gernot Heiser
| first4 = June
| last4 = Andronick
| first5 = David
| last5 = Cock
| first6 = Philip
| last6 = Derrin
| first7 = Dhammika
| last7 = Elkaduwe
| first8 = Kai
| last8 = Engelhardt
| first9 = Rafal
| last9 = Kolanski
| first10 = Michael
| last10 = Norrish
| first11 = Thomas
| last11 = Sewell
| first12 = Harvey
| last12 = Tuch
| first13 = Simon
| last13 = Winwood
| title = seL4: Formal verification of an OS kernel
| booktitle = 22nd ACM Symposium on Operating System Principles
|date=October 2009
| location = Big Sky, MT, USA
| doi =
| url = http://www.sigops.org/sosp/sosp09/papers/klein-sosp09.pdf
}}
</ref> used Haskell as a prototyping language for the OS developer.<ref name="klein-sosp09"/>{{rp|p.2}} At the same time, the Haskell code defined an executable specification with which to reason, for automatic translation by the theorem-proving tool.<ref name="klein-sosp09"/>{{rp|p.3}} The Haskell code thus served as an intermediate prototype before final [[C (programming language)|C]] refinement.<ref name="klein-sosp09"/>{{rp|p.3}}

===Web===
Haskell [[web framework]]s exist,<ref>{{cite web|url=http://www.haskell.org/haskellwiki/Web/Frameworks|title=Web/Frameworks|publisher=}}</ref> including:
* [[Yesod (web framework)|Yesod]]
* [[Snap (web framework)|Snap]]<ref>{{cite web|url=http://snapframework.com/ |title=Snap: A Haskell Web Framework: Home |publisher=Snapframework.com |accessdate=2013-06-26}}</ref>
* [[Miso (web framework)|Miso]]

==Criticism==

Jan-Willem Maessen, in 2002, and [[Simon Peyton Jones]], in 2003, discussed problems associated with lazy evaluation while also acknowledging the theoretical motives for it.<ref>Jan-Willem Maessen. ''Eager Haskell: Resource-bounded execution yields efficient iteration''. Proceedings of the 2002 [[Association for Computing Machinery]] (ACM) SIGPLAN workshop on Haskell.</ref><ref>Simon Peyton Jones. [http://research.microsoft.com/~simonpj/papers/haskell-retrospective ''Wearing the hair shirt: a retrospective on Haskell'']. Invited talk at [[POPL]] 2003.</ref> In addition to purely practical considerations such as improved performance,<ref>{{cite web|url=http://www.haskell.org/pipermail/haskell/2006-June/018127.html|title=Lazy evaluation can lead to excellent performance, such as in The Computer Language Benchmarks Game}}</ref> they note that, in addition to adding some performance overhead, lazy evaluation makes it more difficult for programmers to reason about the performance of their code (particularly its space use).

Bastiaan Heeren, Daan Leijen, and Arjan van IJzendoorn in 2003 also observed some stumbling blocks for Haskell learners: "The subtle syntax and sophisticated type system of Haskell are a double edged sword – highly appreciated by experienced programmers but also a source of frustration among beginners, since the generality of Haskell often leads to cryptic error messages."<ref>{{cite journal|first1=Bastiaan |last1=Heeren |first2=Daan |last2=Leijen |first3=Arjan |last3=van IJzendoorn|year=2003|title=Helium, for learning Haskell|journal=Proceedings of the 2003 [[Association for Computing Machinery|ACM]] [[SIGPLAN]] workshop on Haskell|url=http://www.cs.uu.nl/~bastiaan/heeren-helium.pdf}}</ref> To address these, researchers from Utrecht University developed an advanced interpreter called [[Helium (Haskell)|Helium]], which improved the user-friendliness of error messages by limiting the generality of some Haskell features, and in particular removing support for [[type class]]es.

Ben Lippmeier designed Disciple<ref>{{cite web|url=http://www.haskell.org/haskellwiki/DDC |title=DDC – HaskellWiki |publisher=Haskell.org |date=2010-12-03 |accessdate=2013-06-26}}</ref> as a [[evaluation strategy|strict-by-default]] (lazy by explicit annotation) dialect of Haskell with a type-and-effect system, to address Haskell's difficulties in reasoning about lazy evaluation and in using traditional data structures such as mutable arrays.<ref>Ben Lippmeier, [http://www.cse.unsw.edu.au/~benl/papers/thesis/lippmeier-impure-world.pdf Type Inference and Optimisation for an Impure World], [[Australian National University]] (2010) PhD thesis, chapter 1</ref> He argues (p. 20) that "destructive update furnishes the programmer with two important and powerful tools ... a set of efficient array-like data structures for managing collections of objects, and ... the ability to broadcast a new value to all parts of a program with minimal burden on the programmer."

[[Robert Harper (computer scientist)|Robert Harper]], one of the authors of [[Standard ML]], has given his reasons for not using Haskell to teach introductory programming. Among these are the difficulty of reasoning about resource use with non-strict evaluation, that lazy evaluation complicates the definition of data types and inductive reasoning,<ref>{{cite web|url=http://existentialtype.wordpress.com/2011/04/24/the-real-point-of-laziness/|title=The point of laziness|author=Robert Harper}}
</ref> and the "inferiority" of Haskell's (old) class system compared to ML's module system.<ref>{{cite web|url=http://existentialtype.wordpress.com/2011/04/16/modules-matter-most/|author=Robert Harper|title=Modules matter most.}}
</ref>

It was consistently criticised by developers due to the lack of good management of different versions of a particular library by default build tool, Cabal, in a [[dll hell]]. This has been addressed<ref>[https://www.haskell.org/communities/05-2017/report.pdf Haskell Communities and Activities Report, 32nd ed. May 2017, p. 17: Stack Build Tool, January 2015]</ref> by the release of the [[Stack (Haskell)|Stack]], which manages cabal, to do the work in a build.

Although Haskell has copious educational and conceptual type examples, frequently illustrated with the Integer and String types, their use is not the only way to program in Haskell; Integer type can be replaced, with Int or Word when performance is needed, and String type can be replaced with Text type to handle real-world situations more prudently.<ref>[ ''Real-World Haskell'' ]</ref>

==Related languages==
[[Clean (programming language)|Clean]] is a close, slightly older relative of Haskell. Its biggest deviation from Haskell is in the use of [[uniqueness type]]s instead of monads for I/O and side-effects.

A series of languages inspired by Haskell, but with different type systems, have been developed, including:
* [[Agda (theorem prover)|Agda]], a functional language with [[dependent type]]s
* [[Idris (programming language)|Idris]], a general purpose functional language with [[dependent type]]s, developed at the [[University of St Andrews]]
* [[Epigram (programming language)|Epigram]], a functional language with dependent types suitable for proving properties of programs
* [[Cayenne (programming language)|Cayenne]], with [[dependent type]]s
* [[Ωmega]], strict and more
* [[Elm (programming language)|Elm]], a functional language to create web front-end apps, no support for higher-kinded types

[[Java virtual machine]] (JVM) based:
* [[Frege (programming language)|Frege]], a Haskell-like language with Java's [[Scalar (computing)|scalar]] types and good Java integration.<ref name="frege">{{cite web|url=http://fregepl.blogspot.com|title=Frege Programming Language|publisher=}}</ref><ref name="frege-wiki">{{cite web|url=http://code.google.com/p/frege/|title=Google Code Archive - Long-term storage for Google Code Project Hosting.|publisher=}}</ref><ref>{{cite web|url=http://mmhelloworld.blogspot.com.es/2012/02/hello-world-frege.html|title=mmhelloworld|author=Marimuthu Madasamy|publisher=}}</ref>
* [[Jaskell]], a functional [[scripting language]] that runs in Java VM.<ref>{{cite web|url=http://jaskell.codehaus.org/|title=Codehaus|publisher=|deadurl=yes|archiveurl=https://web.archive.org/web/20060220023022/http://jaskell.codehaus.org/|archivedate=20 February 2006|df=dmy-all}}</ref>
* Eta-lang, which intends to be Haskell on the JVM

Other related languages include:
* [[Curry (programming language)|Curry]], a functional/logic programming language based on Haskell

Haskell has served as a testbed for many new ideas in language design. There have been many Haskell variants produced, exploring new language ideas, including:
* Parallel Haskell:
** From [[Glasgow University]], supports clusters of machines or single multiprocessors.<ref>{{cite web|url=http://www.macs.hw.ac.uk/~dsg/gph/|title=Glasgow Parallel Haskell|publisher=}}</ref><ref>{{cite web|url=http://www.haskell.org/ghc/docs/6.6/html/users_guide/lang-parallel.html|title=7.15. Parallel Haskell|publisher=}}</ref> Also within Haskell is support for Symmetric Multiprocessor parallelism.<ref>{{cite web|url=http://www.haskell.org/ghc/docs/6.6/html/users_guide/sec-using-smp.html|title=4.12. Using SMP parallelism|publisher=}}</ref>
** From [[Massachusetts Institute of Technology|MIT]]<ref>{{cite web|url=http://csg.csail.mit.edu/projects/languages/ph.shtml|title=Computation Structures Group- MIT- LCS|author=Todd Allen Amicon|publisher=}}</ref>
* Distributed Haskell (formerly Goffin) and Eden.{{Citation needed|date=April 2009}}
* Eager Haskell, based on [[speculative execution|speculative evaluation]].
* Several [[object-oriented programming|object-oriented]] versions: Haskell++, and Mondrian.
* [[generic programming#Generic Haskell|Generic Haskell]], a version of Haskell with type system support for [[generic programming]].
* O'Haskell, an extension of Haskell adding [[object-oriented programming|object-orientation]] and [[concurrent programming]] support that "has ... been superseded by [[Timber (programming language)|Timber]]".<ref>{{cite web|url=http://www.haskell.org/haskellwiki/O%27Haskell|title=O'Haskell|publisher=}}</ref>
* Disciple, a strict-by-default (laziness available by annotation) dialect of Haskell that supports destructive update, computational effects, type directed field projections and allied functional aspects.
* [[Hume (programming language)|Hume]], a strict functional language for [[embedded system]]s based on processes as stateless automata over a sort of tuples of one element mailbox channels where the state is kept by feedback into the mailboxes, and a mapping description from outputs to channels as box wiring, with a Haskell-like expression language and syntax.

==Conferences and workshops==
The Haskell community meets regularly for research and development activities. The main events are:
* [[International Conference on Functional Programming]] (ICFP)
* [[Haskell Symposium]] (formerly the Haskell Workshop)
* Haskell Implementors Workshop
* [[Commercial Users of Functional Programming]] (CUFP)

Since 2006, a series of organized ''hackathons'' has occurred, the Hac series, aimed at improving the programming language tools and libraries.<ref>{{cite web |title=Hackathon – HaskellWiki |url=http://haskell.org/haskellwiki/Hackathon}}</ref>



==References==
{{Reflist|30em}}

==Further reading==
; Reports
* {{cite book| editor-first = Simon| editor-last = Peyton Jones| editor-link = Simon Peyton Jones| title = Haskell 98 Language and Libraries: The Revised Report| url = http://haskell.org/onlinereport/| year = 2003| publisher = Cambridge University Press| isbn = 0521826144| ref = harv}}
* {{cite book| editor-first = Simon| editor-last = Marlow| editor-link = Simon Marlow| title = Haskell 2010 Language Report| url= https://www.haskell.org/definition/haskell2010.pdf| year = 2010| publisher = Haskell.org | ref = harv}}
; Textbooks
*{{cite book|first=Antony|last=Davie|title=An Introduction to Functional Programming Systems Using Haskell|publisher=Cambridge University Press|year=1992|isbn=0-521-25830-8}}
*{{cite book|first=Richard|last=Bird|authorlink=Richard Bird (computer scientist)|title=Introduction to Functional Programming using Haskell|edition=2nd|publisher=Prentice Hall Press|year=1998|isbn=0-13-484346-0|url=http://www.cs.ox.ac.uk/publications/books/functional/}}
*{{cite book|first=Paul|last=Hudak|authorlink=Paul Hudak|title=The Haskell School of Expression: Learning Functional Programming through Multimedia|publisher=Cambridge University Press|location=New York|year=2000|isbn=0521643384|url=http://www.cs.yale.edu/homes/hudak/SOE/}}
*{{cite book|first=Graham|last=Hutton|authorlink=Graham Hutton|title=Programming in Haskell|year=2007|publisher=Cambridge University Press|isbn=0521692695|url=http://www.cs.nott.ac.uk/~gmh/book.html}}
*{{Cite book|first1=Bryan|last1=O'Sullivan|authorlink1=Bryan O'Sullivan (computer programmer)|first2=Don|last2=Stewart|authorlink2=Don Stewart (computer programmer)|last3=Goerzen|first3=John|authorlink3=John Goerzen|title=[[Real World Haskell]]|year=2008|publisher=O'Reilly|location=Sebastopol|isbn=0-596-51498-0|postscript= ([http://book.realworldhaskell.org/read/ full text])}}
*{{cite book|first=Simon|last=Thompson|title=Haskell: The Craft of Functional Programming|edition=3rd|publisher=Addison-Wesley|year=2011|isbn=0201882957|url=http://www.haskellcraft.com/}}
*{{cite book|last=Lipovača|first=Miran |title=Learn You a Haskell for Great Good!|url=http://learnyouahaskell.com/|date=April 2011|publisher=No Starch Press|location=San Francisco|isbn=978-1-59327-283-8}} ([http://learnyouahaskell.com/chapters full text])
*{{cite book|first=Richard|last=Bird|authorlink=Richard Bird (computer scientist)|title=Thinking Functionally with Haskell |publisher=Cambridge University Press|year=2014|isbn= 978-1-107-45264-0}}
; Tutorials
*{{cite web|url=http://haskell.org/tutorial/|title=A Gentle Introduction To Haskell, Version 98|date=June 2000|first1=Paul |last1=Hudak |first2=John |last2=Peterson |first3=Joseph |last3=Fasel|work=Haskell.org}}
*[http://hal3.name/docs/daume02yaht.pdf Yet Another Haskell Tutorial], by Hal Daumé III; assumes far less prior knowledge than official tutorial
*{{Cite journal|last=Yorgey|first=Brent|date=12 March 2009|title=The Typeclassopedia|journal=The Monad.Reader|issue=13|pages=17–68|url=http://www.haskell.org/wikiupload/8/85/TMR-Issue13.pdf|postscript={{inconsistent citations}}}}
; History
* {{cite journal| first1 = Paul| last1 = Hudak| authorlink1 = Paul Hudak| first2 = John| last2 = Hughes| authorlink2 = John Hughes (computer scientist)| first3 = Simon| last3 = Peyton Jones| authorlink3 = Simon Peyton Jones| first4 = Philip| last4 = Wadler| authorlink4 = Philip Wadler| title = A History of Haskell: Being Lazy with Class| url = http://research.microsoft.com/~simonpj/papers/history-of-haskell/history.pdf | doi = 10.1145/1238844.1238856| year = 2007| journal = Proceedings of the third ACM [[SIGPLAN]] conference on History of programming languages ([[HOPL]] III)| pages = 12-1–55| isbn = 978-1-59593-766-7|ref=harv}}
* {{cite journal|last=Hamilton|first=Naomi|date=19 September 2008|title=The A-Z of Programming Languages: Haskell|journal=[[Computerworld]]|url=http://www.computerworld.com.au/article/261007/a-z_programming_languages_haskell/}}

==External links==
{{Wikibooks|Haskell}}
{{Wikibooks|Write Yourself a Scheme in 48 Hours}}
*{{Official website}}
*[https://wiki.haskell.org/ Haskell Wiki]
*[https://planet.haskell.org/ Planet Haskell] an aggregator of Haskell related blogs and other Haskell-related news sites
*[http://hackage.haskell.org/ Hackage] – central package archive
*[https://www.haskell.org/hoogle/ Hoogle] – API search engine
*[http://tryhaskell.org/ Try Haskell!] – in-browser interactive tutorial
*[https://www.fpcomplete.com/school School of Haskell] – online tutorials
*[http://adit.io/posts/2013-04-17-functors,_applicatives,_and_monads_in_pictures.html Functors, Applicatives, And Monads In Pictures]
*[http://book.realworldhaskell.org/read/ Real World Haskell] - free to read online
*[http://www.willamette.edu/~fruehr/haskell/evolution.html The Evolution of a Haskell Programmer] – slightly humorous overview of different programming styles in Haskell

{{Authority control}}

{{use dmy dates|date=March 2012}}

{{Programming languages}}

[[Category:Academic programming languages]]
[[Category:Articles with example Haskell code]]
[[Category:Educational programming languages]]
[[Category:Functional languages]]
[[Category:Haskell programming language family| ]]
[[Category:Literate programming]]
[[Category:Pattern matching programming languages]]
[[Category:Programming languages created in 1990]]
[[Category:Statically typed programming languages]]

Haskell

2018-12-23T22:45:59Z

Ihatehumans:

'''Haskell''' is a pure [[functional programming languages|functional programming language]] with roots in [[category theory]]. Free and [[open source]] implementations are available for a variety of operating systems.

==Functions in Haskell==

Functions are the most important structure in Haskell. A function takes a single value as input and returns a single value as output. Clearly it is often desirable to take in more than one argument or give out more than one. This can be done using [[tuples]] or [[lists]] but there is a very mathematically elegant and useful method called [[currying]], named for the logician Haskell Curry.

Functions in Haskell are also values in themselves, allowing Haskell to use [[higher-order functions]].

== Hello World ==

(display "hello world\n")

===External links===
* [http://www.haskell.org The HaskellWiki]

[[Category:Programming Languages]]