Added optional Lua lexer support.

This support is disabled by default and must be enabled via compile-time option.

1 files changed, 41 insertions, 0 deletions

diff --git a/lexlua/gherkin.lua b/lexlua/gherkin.lua
new file mode 100644
index 000000000..f4a7924db
--- /dev/null
+++ b/lexlua/gherkin.lua
@@ -0,0 +1,41 @@
+-- Copyright 2015-2018 Jason Schindler. See License.txt.
+-- Gherkin (https://github.com/cucumber/cucumber/wiki/Gherkin) LPeg lexer.
+
+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('gherkin', {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[[
+  And Background But Examples Feature Given Outline Scenario Scenarios Then When
+]]))
+
+-- Strings.
+local doc_str = '"""' * (lexer.any - '"""')^0 * P('"""')^-1
+local dq_str = lexer.delimited_range('"')
+lex:add_rule('string', token(lexer.STRING, doc_str + dq_str))
+
+-- Comments.
+lex:add_rule('comment', token(lexer.COMMENT, '#' * lexer.nonnewline^0))
+
+-- Numbers.
+local number = token(lexer.NUMBER, lexer.float + lexer.integer)
+
+-- Tags.
+lex:add_rule('tag', token('tag', '@' * lexer.word^0))
+lex:add_style('tag', lexer.STYLE_LABEL)
+
+-- Placeholders.
+lex:add_rule('placeholder', token('placeholder', lexer.nested_pair('<', '>')))
+lex:add_style('placeholder', lexer.STYLE_VARIABLE)
+
+-- Examples.
+lex:add_rule('example', token('example', '|' * lexer.nonnewline^0))
+lex:add_style('example', lexer.STYLE_NUMBER)
+
+return lex