Add Typst lexer

lexers/typst.lua

@@ -0,0 +1,69 @@
+-- Copyright 2006-2021 Mitchell. See LICENSE.
+-- ? LPeg lexer.
+
+local lexer = require('lexer')
+local token, word_match = lexer.token, lexer.word_match
+local P, S = lpeg.P, lpeg.S
+
+local lex = lexer.new('?')
+
+lex:add_rule('variable', token(lexer.VARIABLE, lexer.to_eol('#')))
+
+-- Whitespace.
+local ws = token(lexer.WHITESPACE, S(' \t')^1 + S('\v\r\n')^1)
+lex:add_rule('whitespace', ws)
+
+-- Span elements.
+lex:add_rule('escape', token(lexer.DEFAULT, P('\\') * 1))
+
+-- Keywords.
+lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
+  'set'
+]]))
+
+lex:add_rule('function', token(lexer.FUNCTION, word_match[[
+  'text', 'page'
+]]))
+
+
+-- Headers.
+local function h(n) return token('h' .. n, lexer.to_eol(lexer.starts_line(string.rep('=', n)))) end
+lex:add_rule('header', h(6) + h(5) + h(4) + h(3) + h(2) + h(1))
+local font_size = tonumber(lexer.property_expanded['style.default']:match('size:(%d+)')) or 10
+local function add_header_style(n)
+  lex:add_style('h' .. n, {fore = lexer.colors.red, size = (font_size + (6 - n))})
+end
+for i = 1, 6 do add_header_style(i) end
+
+-- Lists.
+lex:add_rule('list', token('list',
+  lexer.starts_line(S(' \t')^0 * (S('+') + lexer.digit^1 * '.')) * S(' \t')))
+lex:add_style('list', lexer.styles.constant)
+
+
+-- Identifiers.
+lex:add_rule('identifier', token(lexer.IDENTIFIER, lexer.word))
+
+-- Strings.
+local sq_str = lexer.range("'")
+local dq_str = lexer.range('"')
+lex:add_rule('string', token(lexer.STRING, sq_str + dq_str))
+
+
+-- Comments.
+local line_comment = lexer.to_eol('//', true)
+local block_comment = lexer.range('/*', '*/')
+lex:add_rule('comment', token(lexer.COMMENT, line_comment + block_comment))
+
+-- Numbers.
+lex:add_rule('number', token(lexer.NUMBER, lexer.number))
+
+-- Operators.
+lex:add_rule('operator', token(lexer.OPERATOR, S('+-/*%<>!=^&|?~:;,.()[]{}')))
+
+-- Fold points.
+lex:add_fold_point(lexer.KEYWORD, 'start', 'end')
+lex:add_fold_point(lexer.OPERATOR, '{', '}')
+lex:add_fold_point(lexer.COMMENT, lexer.fold_consecutive_lines('#'))
+
+return lex