Added optional Lua lexer support.

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

1 files changed, 56 insertions, 0 deletions

diff --git a/lexlua/forth.lua b/lexlua/forth.lua
new file mode 100644
index 000000000..086ce780c
--- /dev/null
+++ b/lexlua/forth.lua
@@ -0,0 +1,56 @@
+-- Copyright 2006-2018 Mitchell mitchell.att.foicica.com. See License.txt.
+-- Forth LPeg lexer.
+-- Contributions from Joseph Eib.
+
+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('forth')
+
+-- Whitespace.
+lex:add_rule('whitespace', token(lexer.WHITESPACE, lexer.space^1))
+
+-- Strings.
+local c_str = 'c' * lexer.delimited_range('"', true, true)
+local s_str = 's' * lexer.delimited_range('"', true, true)
+local s_bs_str = 's\\' * lexer.delimited_range('"', true, false)
+local dot_str = '.' * lexer.delimited_range('"', true, true)
+local dot_paren_str = '.' * lexer.delimited_range('()', true, true, false)
+local abort_str = 'abort' * lexer.delimited_range('"', true, true)
+lex:add_rule('string', token(lexer.STRING, c_str + s_str + s_bs_str + dot_str +
+                                           dot_paren_str + abort_str))
+
+-- Keywords.
+lex:add_rule('keyword', token(lexer.KEYWORD, word_match[[
+  #> #s */ */mod +loop , . .r /mod 0< 0<> 0> 0= 1+ 1- 2! 2* 2/ 2>r 2@ 2drop 2dup
+  2over 2r> 2r@ 2swap :noname <# <> >body >in >number >r ?do ?dup @ abort abs
+  accept action-of again align aligned allot and base begin bl buffer: c! c, c@
+  case cell+ cells char char+ chars compile, constant, count cr create decimal
+  defer defer! defer@ depth do does> drop dup else emit endcase endof
+  environment? erase evaluate execute exit false fill find fm/mod here hex hold
+  holds i if immediate invert is j key leave literal loop lshift m* marker max
+  min mod move negate nip of or over pad parse parse-name pick postpone quit r>
+  r@ recurse refill restore-input roll rot rshift s>d save-input sign sm/rem
+  source source-id space spaces state swap to then true tuck type u. u.r u> u<
+  um* um/mod unloop until unused value variable while within word xor ['] [char]
+  [compile]
+]], true))
+
+-- Identifiers.
+lex:add_rule('identifier', token(lexer.IDENTIFIER, (lexer.alnum +
+                                                    S('+-*=<>.?/\'%,_$#'))^1))
+
+-- Comments.
+local line_comment = S('|\\') * lexer.nonnewline^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, P('-')^-1 * lexer.digit^1 *
+                                           (S('./') * lexer.digit^1)^-1))
+
+-- Operators.
+lex:add_rule('operator', token(lexer.OPERATOR, S(':;<>+*-/[]#')))
+
+return lex