Added optional Lua lexer support.

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

1 files changed, 88 insertions, 0 deletions

diff --git a/lexlua/xml.lua b/lexlua/xml.lua
new file mode 100644
index 000000000..d709ef3e5
--- /dev/null
+++ b/lexlua/xml.lua
@@ -0,0 +1,88 @@
+-- Copyright 2006-2018 Mitchell mitchell.att.foicica.com. See License.txt.
+-- XML LPeg lexer.
+
+local lexer = require('lexer')
+local token, word_match = lexer.token, lexer.word_match
+local P, R, S, V = lpeg.P, lpeg.R, lpeg.S, lpeg.V
+
+local lex = lexer.new('xml')
+
+-- Whitespace.
+local ws = token(lexer.WHITESPACE, lexer.space^1)
+lex:add_rule('whitespace', ws)
+
+-- Comments and CDATA.
+lex:add_rule('comment', token(lexer.COMMENT, '<!--' * (lexer.any - '-->')^0 *
+                                             P('-->')^-1))
+lex:add_rule('cdata', token('cdata', '<![CDATA[' * (lexer.any - ']]>')^0 *
+                                     P(']]>')^-1))
+lex:add_style('cdata', lexer.STYLE_COMMENT)
+
+local alpha = R('az', 'AZ', '\127\255')
+local word_char = lexer.alnum + S('_-:.??')
+local identifier = (alpha + S('_-:.??')) * word_char^0
+
+-- Doctypes and other markup tags.
+lex:add_rule('doctype', token('doctype', P('<!DOCTYPE')) * ws *
+                        token('doctype', identifier) * (ws * identifier)^-1 *
+                        (1 - P('>'))^0 *  token('doctype', '>'))
+lex:add_style('doctype', lexer.STYLE_COMMENT)
+
+-- Processing instructions.
+lex:add_rule('proc_insn', token('proc_insn', P('<?') * (1 - P('?>'))^0 *
+                                             P('?>')^-1))
+lex:add_style('proc_insn', lexer.STYLE_COMMENT)
+
+-- Elements.
+local namespace = token(lexer.OPERATOR, ':') * token('namespace', identifier)
+lex:add_rule('element', token('element', '<' * P('/')^-1 * identifier) *
+                        namespace^-1)
+lex:add_style('element', lexer.STYLE_KEYWORD)
+lex:add_style('namespace', lexer.STYLE_CLASS)
+
+-- Closing tags.
+lex:add_rule('close_tag', token('element', P('/')^-1 * '>'))
+
+-- Attributes.
+lex:add_rule('attribute', token('attribute', identifier) * namespace^-1 *
+                          #(lexer.space^0 * '='))
+lex:add_style('attribute', lexer.STYLE_TYPE)
+
+-- TODO: performance is terrible on large files.
+local in_tag = P(function(input, index)
+  local before = input:sub(1, index - 1)
+  local s, e = before:find('<[^>]-$'), before:find('>[^<]-$')
+  if s and e then return s > e and index or nil end
+  if s then return index end
+  return input:find('^[^<]->', index) and index or nil
+end)
+
+-- Equals.
+--lex:add_rule('equal', token(lexer.OPERATOR, '=')) -- * in_tag
+
+-- Strings.
+lex:add_rule('string', #S('\'"') * lexer.last_char_includes('=') *
+                       token(lexer.STRING,
+                             lexer.delimited_range("'", false, true) +
+                             lexer.delimited_range('"', false, true)))
+
+-- Numbers.
+lex:add_rule('number', #lexer.digit * lexer.last_char_includes('=') *
+                       token(lexer.NUMBER, lexer.digit^1 * P('%')^-1))--*in_tag)
+
+-- Entities.
+lex:add_rule('entity', token('entity', '&' * word_match[[
+  lt gt amp apos quot
+]] * ';'))
+lex:add_style('entity', lexer.STYLE_OPERATOR)
+
+-- Fold Points.
+local function disambiguate_lt(text, pos, line, s)
+  return not line:find('^</', s) and 1 or -1
+end
+lex:add_fold_point('element', '<', disambiguate_lt)
+lex:add_fold_point('element', '/>', -1)
+lex:add_fold_point(lexer.COMMENT, '<!--', '-->')
+lex:add_fold_point('cdata', '<![CDATA[', ']]>')
+
+return lex