Antlr / peggy tests

packages/less/.eslintignore

@@ -3,4 +3,5 @@ dist/*
 tmp/*
 lib/*
 test/browser/less.min.js
-node_modules
+node_modules
+src/parser/less.*

packages/less/.gitignore

@@ -6,4 +6,5 @@ test/browser/less.min.js.map
 test/sourcemaps/**/*.map
 test/sourcemaps/*.map
 test/sourcemaps/*.css
-test/less-bom
+test/less-bom
+.antlr

packages/less/package.json

@@ -134,6 +134,7 @@
 	"dependencies": {
 		"copy-anything": "^2.0.1",
 		"parse-node-version": "^1.0.1",
+		"peggy": "^3.0.2",
 		"tslib": "^2.3.0"
 	}
 }

packages/less/src/parser-antlr/CssLexer.g4

@@ -0,0 +1,135 @@
+/**
+ * references:
+ * https://github.com/antlr/grammars-v4/blob/master/css3/css3.g4
+ * https://www.lifewire.com/css2-vs-css3-3466978
+ * https://www.w3.org/TR/css-syntax-3/
+ * https://github.com/jesscss/jess/blob/master/packages/css-parser/src/cssTokens.ts
+ */
+lexer grammar CssLexer;
+
+fragment Newline
+  : '\\n' | '\\r' '\\n'? | '\\f'
+  ;
+
+fragment WS
+  : ' ' | '\\t' | Newline
+  ;
+
+/** 
+ * Uses nongreedy wildcard
+ * @see https://github.com/antlr/antlr4/blob/master/doc/wildcard.md
+ */
+fragment Comment
+  : '/*' .*? '*/'
+  ;
+
+fragment Digit
+  : '0'..'9'
+  ;
+
+fragment Hex
+  : Digit
+  | 'a'..'f'
+  | 'A'..'F'
+  ;
+
+fragment Unicode
+  : '\\' Hex (Hex Hex Hex Hex Hex)? WS? // 1 or 6 hex digits
+  ;
+
+fragment Escape
+  : Unicode
+  | '\\' ~[\r\n\f0-9a-fA-F]
+  ;
+
+fragment DoubleString
+  : '"' ('\\' | ~[\n\r\f"] | Newline | Escape) '"'
+  ;
+
+fragment SingleString
+  : '\'' ('\\' | ~[\n\r\f'] | Newline | Escape) '\''
+  ;
+
+fragment String
+  : DoubleString | SingleString
+  ;
+
+fragment NonAscii
+  : '\u0240'..'\uffff'
+  ;
+
+fragment NmStart
+  : '_' | NonAscii | Escape
+  ;
+
+fragment NmChar
+  : [_a-zA-Z0-9-]
+  | NonAscii
+  | Escape
+  ;
+
+fragment Ident
+  : '-?' NmStart NmChar*
+  ;
+
+/** Reference: https://www.w3.org/TR/css-syntax-3/#consume-url-token */
+fragment UrlFragment
+  : (~(
+    '('
+    | '"'
+    | '\''
+    // Non-printable
+    | '\u0000'..'\u0008'
+    | '\u000b'
+    | '\u000e'..'\u001f'
+    | '\u007f'
+  ))*
+  ;
+
+fragment Integer
+  : ('+' | '-')? ('0'..'9')+
+  ;
+
+fragment Exp
+  : [eE][+-]Digit+
+  ;
+
+/** Any number that's not simply an integer e.g. 1.1 or 1e+1 */
+fragment Number
+  : ('+' | '-')?
+  (
+    Digit* '.' Digit+ Exp?
+    | Digit+ Exp?
+  )
+  ;
+
+fragment WSorComment
+  : (WS | Comment)*
+  ;
+
+fragment Gt   : '>';
+
+CompareOp   : (Gt | '<') '='?;
+LCurly      : '{';
+RCurly      : '}';
+LParen      : '(';
+RParen      : ')';
+LSquare     : '[';
+RSquare     : ']';
+Semi        : ';';
+
+Plus : '+';
+Minus       : '-';
+Comma       : ',';
+Divide      : '/';
+Eq          : '=';
+Star        : '*';
+Tilde       : '~';
+
+Combinator  : Plus | Gt | Tilde;
+
+
+
+
+
+

packages/less/src/parser-antlr/CssParser.g4

@@ -0,0 +1,38 @@
+/**
+ * @see https://www.w3.org/TR/css-syntax-3/#parser-diagrams
+ */
+
+parser grammar CssParser;
+
+stylesheet
+  : (cdo | cdc | WS | qualified_rule | at_rule)* EOF
+  ;
+
+rule_list
+  : (WS | qualified_rule | at_rule)*
+  ;
+
+at_rule
+  : At_keyword at_rule_value* (curly_block | ';')
+  ;
+
+qualified_rule
+  : qualified_rule_value* qualified_rule_block
+  ;
+
+declaration_list
+  : WS* (
+    declaration (';' declaration_list)?
+    | at_rule declaration_list
+  )
+  ;
+
+declaration
+  : Ident WS* ':' declaration_value* important?
+  ;
+
+important
+  : '!' WS* Important WS*
+  ;
+
+