-- Copyright 2006-2018 Mitchell mitchell.att.foicica.com. See License.txt.
|
-- Haskell LPeg lexer.
|
-- Modified by Alex Suraci.
|
|
local lexer = require('lexer')
|
local token, word_match = lexer.token, lexer.word_match
|
local P, R, S = lpeg.P, lpeg.R, lpeg.S
|
|
local lex = lexer.new('haskell', {fold_by_indentation = true})
|
|
-- Whitespace.
|
lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
|
|
-- Keywords.
|
lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
|
case class data default deriving do else if import in infix infixl infixr
|
instance let module newtype of then type where _ as qualified hiding
|
]]))
|
|
local word = (lexer.alnum + S("._'#"))^0
|
local op = lexer.punct - S('()[]{}')
|
|
-- Types & type constructors.
|
lex:add_rule('type', token(lexer.TYPE, (lexer.upper * word) +
|
(":" * (op^1 - ":"))))
|
|
-- Identifiers.
|
lex:add_rule('identifier', token(lexer.IDENTIFIER, (lexer.alpha + '_') * word))
|
|
-- Strings.
|
lex:add_rule('string', token(lexer.STRING, lexer.delimited_range("'", true) +
|
lexer.delimited_range('"')))
|
|
-- Comments.
|
local line_comment = '--' * lexer.nonnewline_esc^0
|
local block_comment = '{-' * (lexer.any - '-}')^0 * P('-}')^-1
|
lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))
|
|
-- Numbers.
|
lex:add_rule('number', token(lexer.NUMBER, lexer.float + lexer.integer))
|
|
-- Operators.
|
lex:add_rule('operator', token(lexer.OPERATOR, op))
|
|
return lex
|
