lexer: add lexer for pure

Ref: http://purelang.bitbucket.org/

Closes #106

2 files changed, 55 insertions, 0 deletions

diff --git a/lexers/lexer.lua b/lexers/lexer.lua
index 2cb7ad0..a6b27bd 100644
--- a/lexers/lexer.lua
+++ b/lexers/lexer.lua
@@ -1668,6 +1668,7 @@ local files = {
 	[".eps|.ps"] = "ps",
 	[".prolog"] = "prolog",
 	[".props|.properties"] = "props",
+	[".pure"] = "pure",
 	[".sc|.py|.pyw"] = "python",
 	[".R|.Rout|.Rhistory|.Rt|Rout.save|Rout.fail"] = "rstats",
 	[".r|.reb"] = "rebol",
diff --git a/lexers/pure.lua b/lexers/pure.lua
new file mode 100644
index 0000000..a376591
--- /dev/null
+++ b/lexers/pure.lua
@@ -0,0 +1,54 @@
+-- pure LPeg lexer.
+
+local l = require('lexer')
+local token, word_match = l.token, l.word_match
+local P, R, S = lpeg.P, lpeg.R, lpeg.S
+
+local M = {_NAME = 'pure'}
+
+-- Whitespace.
+local ws = token(l.WHITESPACE, l.space^1)
+
+-- Comments.
+local line_comment = '//' * l.nonnewline_esc^0
+local block_comment = '/*' * (l.any - '*/')^0 * P('*/')^-1
+local comment = token(l.COMMENT, line_comment + block_comment)
+
+-- Strings.
+local sq_str = P('L')^-1 * l.delimited_range("'", true)
+local dq_str = P('L')^-1 * l.delimited_range('"', true)
+local string = token(l.STRING, sq_str + dq_str)
+
+-- Numbers.
+local bin = '0' * S('Bb') * S('01')^1
+local hex = '0' * S('Xx') * (R('09') + R('af') + R('AF'))^1
+local int = R('09')^1
+local exp = S('Ee') * S('+-')^-1 * int
+local flt = int * ('.' * int)^-1 * exp + int^-1 * '.' * int * exp^-1
+local number = token(l.NUMBER, flt + bin + hex + int * P('L')^-1)
+
+-- Keywords.
+local keyword = token(l.KEYWORD, word_match{
+  'namespace', 'with', 'end', 'using', 'interface', 'extern', 'let',
+  'const', 'def', 'type', 'public', 'private', 'nonfix', 'outfix',
+  'infix', 'infixl', 'infixr', 'prefix', 'postfix', 'if', 'otherwise',
+  'when', 'case', 'of', 'then', 'else'
+})
+
+-- Identifiers.
+local identifier = token(l.IDENTIFIER, l.word)
+
+-- Operators.
+local operator = token(l.OPERATOR, S('+-/*%<>~!=^&|?~:;,.()[]{}@\\'))
+
+M._rules = {
+  {'whitespace', ws},
+  {'keyword', keyword},
+  {'number', number},
+  {'identifier', identifier},
+  {'string', string},
+  {'comment', comment},
+  {'operator', operator},
+}
+
+return M