1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
|
local info = {
version = 1.001,
comment = "scintilla lpeg lexer for bnf",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files",
}
-- will replace the one in metafun
local global, lpeg = _G, lpeg
local P, R, S = lpeg.P, lpeg.R, lpeg.S
local lexer = require("scite-context-lexer")
local context = lexer.context
local patterns = context.patterns
local token = lexer.token
local exact_match = lexer.exact_match
local bnflexer = lexer.new("bnf","scite-context-lexer-bnf")
local whitespace = bnflexer.whitespace
-- from wikipedia:
--
-- <syntax> ::= <rule> | <rule> <syntax>
-- <rule> ::= <opt-whitespace> "<" <rule-name> ">" <opt-whitespace> "::=" <opt-whitespace> <expression> <line-end>
-- <opt-whitespace> ::= " " <opt-whitespace> | ""
-- <expression> ::= <list> | <list> <opt-whitespace> "|" <opt-whitespace> <expression>
-- <line-end> ::= <opt-whitespace> <EOL> | <line-end> <line-end>
-- <list> ::= <term> | <term> <opt-whitespace> <list>
-- <term> ::= <literal> | "<" <rule-name> ">"
-- <literal> ::= '"' <text1> '"' | "'" <text2> "'"
-- <text1> ::= "" | <character1> <text1>
-- <text2> ::= "" | <character2> <text2>
-- <character> ::= <letter> | <digit> | <symbol>
-- <letter> ::= "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" | "J" | "K" | "L" | "M" | "N" | "O" | "P" | "Q" | "R" | "S" | "T" | "U" | "V" | "W" | "X" | "Y" | "Z" | "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" | "i" | "j" | "k" | "l" | "m" | "n" | "o" | "p" | "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x" | "y" | "z"
-- <digit> ::= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
-- <symbol> ::= "|" | " " | "-" | "!" | "#" | "$" | "%" | "&" | "(" | ")" | "*" | "+" | "," | "-" | "." | "/" | ":" | ";" | ">" | "=" | "<" | "?" | "@" | "[" | "\" | "]" | "^" | "_" | "`" | "{" | "}" | "~"
-- <character1> ::= <character> | "'"
-- <character2> ::= <character> | '"'
-- <rule-name> ::= <letter> | <rule-name> <rule-char>
-- <rule-char> ::= <letter> | <digit> | "-"
local anything = patterns.anything
local separator = P("|")
local left = P("<")
local right = P(">")
local space = S(" \t\n\r\f")
local spaces = space^1
local letter = R("AZ","az")
local digit = R("09")
local symbol = S([[| -!#$%&()*+,-./:;>=<?@[\]^_`{}~]])
local text = (letter + digit + symbol^0)
local name = letter * (letter + digit + P("-"))^0
local becomes = P("::=")
local extra = P("|")
local single = P("'")
local double = P('"')
local t_spacing = token(whitespace,space^1)
local t_term = token("command",left)
* token("text",name)
* token("command",right)
local t_text = token("quote",single)
* token("text",text)
* token("quote",single)
+ token("quote",double)
* token("text",text)
* token("quote",double)
local t_becomes = token("operator",becomes)
local t_extra = token("extra",extra)
local t_rest = token("default",anything)
bnflexer._rules = {
{ "whitespace", t_spacing },
{ "term", t_term },
{ "text", t_text },
{ "becomes", t_becomes },
{ "extra", t_extra },
{ "rest", t_rest },
}
bnflexer._tokenstyles = context.styleset
bnflexer._foldpattern = left + right
bnflexer._foldsymbols = {
_patterns = {
"<",
">",
},
["grouping"] = {
["<"] = 1,
[">"] = -1,
},
}
return bnflexer
|
