Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Agda (programming language)
open-in-new
<p>Agda is a <a href="/facts/Dependent_type/wCeQI7ds">dependently typed</a> <a href="/facts/Functional_programming/cdxqPEIM">functional</a> <a href="/facts/Programming_language/cWTYbgWa">programming language</a> originally developed by Ulf Norell at <a href="/facts/Chalmers_University_of_Technology/L9PhS9LV">Chalmers University of Technology</a> with implementation described in his PhD thesis. The original Agda system was developed at Chalmers by Catarina Coquand in 1999. The current version, originally named Agda 2, is a full rewrite, which should be considered a new language that shares a name and tradition. </p><p>Agda is also a <a href="/facts/Proof_assistant/hjFGxLPn">proof assistant</a> based on the <i>propositions-as-types</i> paradigm (<a href="/facts/Curry%E2%80%93Howard_correspondence/Q3eVu60u">Curry–Howard correspondence</a>), but unlike <a href="/facts/Coq_(software)/7oBXgLCE">Coq</a>, has no separate <i>tactics</i> language, and proofs are written in a functional programming style. The language has ordinary programming constructs such as <a href="/facts/Data_type/fcx5hgVL">data types</a>, <a href="/facts/Pattern_matching/CEwptMs9">pattern matching</a>, <a href="/facts/Record_(computer_science)/1fvSgenB">records</a>, <a href="/facts/Let_expression/NtjjgS2U">let expressions</a> and modules, and a <a href="/facts/Haskell/ydEsHuGy">Haskell</a>-like <a href="/facts/Syntax_(programming_languages)/zM5oInza">syntax</a>. The system has <a href="/facts/Emacs/BvGxuAxQ">Emacs</a>, <a href="/facts/Atom_(text_editor)/fHN07lHW">Atom</a>, and <a href="/facts/VS_Code/YsBDgKlK">VS Code</a> interfaces but can also be run in <a href="/facts/Batch_processing/hKY2rX3N">batch processing</a> mode from a <a href="/facts/Command-line_interface/R9JpGmXQ">command-line interface</a>. </p><p>Agda is based on Zhaohui Luo's unified theory of dependent types (UTT), a type theory similar to <a href="/facts/Intuitionistic_type_theory/qwkrpKlP">Martin-Löf type theory</a>. </p><p>Agda is named after the <a href="/facts/Swedish_language/1DkSIXkH">Swedish</a> song "Hönan Agda", written by <a href="/facts/Cornelis_Vreeswijk/uBaSLcgL">Cornelis Vreeswijk</a>, which is about a <a href="/facts/Chicken/RD2eTd83">hen</a> named Agda. This alludes to the name of the theorem prover <a href="/facts/Coq_(software)/7oBXgLCE">Coq</a>, which was named after <a href="/facts/Thierry_Coquand/jG36x5By">Thierry Coquand</a>. </p>