3º. 2º cuatrimestre. Itinerario de Computación. Grado en Ingeniería Informática. ULL
See https://github.com/pegjs/pegjs/blob/master/src/parser.pegjs for latest version
[~/srcPLgrado/pegjs(master)]$ cat src/parser.pegjs
grammar
= __ initializer? rule+
initializer
= action semicolon?
rule
= identifier string? equals expression semicolon?
expression
= choice
choice
= sequence (slash sequence)*
sequence
= labeled* action
/ labeled*
labeled
= identifier colon prefixed
/ prefixed
prefixed
= dollar suffixed
/ and action
/ and suffixed
/ not action
/ not suffixed
/ suffixed
suffixed
= primary question
/ primary star
/ primary plus
/ primary
primary
= identifier !(string? equals)
/ literal
/ class
/ dot
/ lparen expression rparen
/* "Lexical" elements */
action "action"
= braced __
braced
= "{" (braced / nonBraceCharacters)* "}"
nonBraceCharacters
= nonBraceCharacter+
nonBraceCharacter
= [^{}]
equals = "=" __
colon = ":" __
semicolon = ";" __
slash = "/" __
and = "&" __
not = "!" __
dollar = "$" __
question = "?" __
star = "*" __
plus = "+" __
lparen = "(" __
rparen = ")" __
dot = "." __
/*
* Modeled after ECMA-262, 5th ed., 7.6, but much simplified:
*
* * no Unicode escape sequences
*
* * "Unicode combining marks" and "Unicode connection punctuation" can't be
* part of the identifier
*
* * only [a-zA-Z] is considered a "Unicode letter"
*
* * only [0-9] is considered a "Unicode digit"
*
* The simplifications were made just to make the implementation little bit
* easier, there is no "philosophical" reason behind them.
*
* Contrary to ECMA 262, the "$" character is not valid because it serves other
* purpose in the grammar.
*/
identifier "identifier"
= (letter / "_") (letter / digit / "_")* __
/*
* Modeled after ECMA-262, 5th ed., 7.8.4. (syntax & semantics, rules only
* vaguely).
*/
literal "literal"
= (doubleQuotedString / singleQuotedString) "i"? __
string "string"
= (doubleQuotedString / singleQuotedString) __
doubleQuotedString
= '"' doubleQuotedCharacter* '"'
doubleQuotedCharacter
= simpleDoubleQuotedCharacter
/ simpleEscapeSequence
/ zeroEscapeSequence
/ hexEscapeSequence
/ unicodeEscapeSequence
/ eolEscapeSequence
simpleDoubleQuotedCharacter
= !('"' / "\\" / eolChar) .
singleQuotedString
= "'" singleQuotedCharacter* "'"
singleQuotedCharacter
= simpleSingleQuotedCharacter
/ simpleEscapeSequence
/ zeroEscapeSequence
/ hexEscapeSequence
/ unicodeEscapeSequence
/ eolEscapeSequence
simpleSingleQuotedCharacter
= !("'" / "\\" / eolChar) .
class "character class"
= "[" "^"? (classCharacterRange / classCharacter)* "]" "i"? __
classCharacterRange
= classCharacter "-" classCharacter
classCharacter
= bracketDelimitedCharacter
bracketDelimitedCharacter
= simpleBracketDelimitedCharacter
/ simpleEscapeSequence
/ zeroEscapeSequence
/ hexEscapeSequence
/ unicodeEscapeSequence
/ eolEscapeSequence
simpleBracketDelimitedCharacter
= !("]" / "\\" / eolChar) .
simpleEscapeSequence
= "\\" !(digit / "x" / "u" / eolChar) .
zeroEscapeSequence
= "\\0" !digit
hexEscapeSequence
= "\\x" hexDigit hexDigit)
unicodeEscapeSequence
= "\\u" hexDigit hexDigit hexDigit hexDigit)
eolEscapeSequence
= "\\" eol
digit
= [0-9]
hexDigit
= [0-9a-fA-F]
letter
= lowerCaseLetter
/ upperCaseLetter
lowerCaseLetter
= [a-z]
upperCaseLetter
= [A-Z]
__ = (whitespace / eol / comment)*
/* Modeled after ECMA-262, 5th ed., 7.4. */
comment "comment"
= singleLineComment
/ multiLineComment
singleLineComment
= "//" (!eolChar .)*
multiLineComment
= "/*" (!"*/" .)* "*/"
/* Modeled after ECMA-262, 5th ed., 7.3. */
eol "end of line"
= "\n"
/ "\r\n"
/ "\r"
/ "\u2028"
/ "\u2029"
eolChar
= [\n\r\u2028\u2029]
/* Modeled after ECMA-262, 5th ed., 7.2. */
whitespace "whitespace"
= [ \t\v\f\u00A0\uFEFF\u1680\u180E\u2000-\u200A\u202F\u205F\u3000]
[~/.../pegjs/examples(master)]$ node
Welcome to Node.js v12.10.0.
Type ".help" for more information.
> peg = require("pegjs")
{
VERSION: '0.10.0',
GrammarError: [Function: GrammarError],
parser: {
SyntaxError: [Function: peg$SyntaxError] { buildMessage: [Function] },
parse: [Function: peg$parse]
},
compiler: {
visitor: { build: [Function: build] },
passes: { check: [Object], transform: [Object], generate: [Object] },
compile: [Function: compile]
},
generate: [Function: generate]
}
> grammar = "s = 'a'";
"s = 'a'"
> ast = peg.parser.parse(grammar)
{
type: 'grammar',
initializer: null,
rules: [
{
type: 'rule',
name: 's',
expression: [Object],
location: [Object]
}
],
location: {
start: { offset: 0, line: 1, column: 1 },
end: { offset: 7, line: 1, column: 8 }
}
}
> ins = x => util.inspect(x, {depth:null})
> ins(ast)
'{\n' +
" type: 'grammar',\n" +
' initializer: null,\n' +
' rules: [\n' +
' {\n' +
" type: 'rule',\n" +
" name: 's',\n" +
' expression: {\n' +
" type: 'literal',\n" +
" value: 'a',\n" +
' ignoreCase: false,\n' +
' location: {\n' +
' start: { offset: 4, line: 1, column: 5 },\n' +
' end: { offset: 7, line: 1, column: 8 }\n' +
' }\n' +
' },\n' +
' location: {\n' +
' start: { offset: 0, line: 1, column: 1 },\n' +
' end: { offset: 7, line: 1, column: 8 }\n' +
' }\n' +
' }\n' +
' ],\n' +
' location: {\n' +
' start: { offset: 0, line: 1, column: 1 },\n' +
' end: { offset: 7, line: 1, column: 8 }\n' +
' }\n' +
'}'