Pratt parsing and explicit node elision

examples/c/src/c.llw

@@ -53,7 +53,7 @@ string_literal:
 ;
 /// 6.5.1.1
 generic_assoc_list:
-  generic_association (',' generic_association)* @
+  generic_association (',' generic_association)*
 ;
 /// 6.5.1.1
 generic_association:
@@ -70,15 +70,15 @@ postfix_expr:
   | '--' @post_dec_expr
   )
 | ?1 '(' type_name ')' '{' [initializer_list [',']] '}' @compound_literal
-| primary_expr
+| primary_expr ^
 ;
 /// 6.5.2
 argument_expression_list:
-  assignment_expr (',' assignment_expr)* @
+  assignment_expr (',' assignment_expr)*
 ;
 /// 6.5.3
 unary_expr:
-  postfix_expr
+  postfix_expr ^
 | '++' unary_expr @pre_inc_expr
 | '--' unary_expr @pre_dec_expr
 | '__extension__' cast_expr @extension_expr // GNU extension
@@ -93,7 +93,7 @@ unary_expr:
 /// 6.5.4
 cast_expr:
   ?1 '(' type_name ')' cast_expr
-| unary_expr
+| unary_expr ^
 ;
 /// 6.5.5 - 6.5.14
 bin_expr:
@@ -107,27 +107,27 @@ bin_expr:
 | bin_expr '|' bin_expr
 | bin_expr '&&' bin_expr
 | bin_expr '||' bin_expr
-| cast_expr
+| cast_expr ^
 ;
 /// 6.5.15 (empty second argument is GNU extension)
-conditional_expr:
-  bin_expr ['?' [expr] ':' conditional_expr]
+conditional_expr^:
+  bin_expr ['?' [expr] ':' conditional_expr >]
 ;
 /// 6.5.16
-assignment_expr:
-  conditional_expr [('=' | '*=' | '/=' | '%=' | '+=' | '-=' | '<<=' | '>>=' | '&=' | '^=' | '|=') assignment_expr]
+assignment_expr^:
+  conditional_expr [('=' | '*=' | '/=' | '%=' | '+=' | '-=' | '<<=' | '>>=' | '&=' | '^=' | '|=') assignment_expr >]
 ;
 /// 6.5.17
-expr:
+expr^:
   comma_expr
 ;
 /// 6.5.17
 comma_expr:
   comma_expr ',' assignment_expr
-| assignment_expr
+| assignment_expr ^
 ;
 /// 6.6
-constant_expr:
+constant_expr^:
   conditional_expr
 ;
 
@@ -145,11 +145,11 @@ declaration_specifiers:
 ;
 /// 6.7
 init_declarator_list:
-  init_declarator (',' gnu_attributes init_declarator)* @
+  init_declarator (',' gnu_attributes init_declarator)*
 ;
 /// 6.7
 init_declarator:
-  declarator [gnu_asm] gnu_attributes ['=' initializer] @
+  declarator [gnu_asm] gnu_attributes ['=' initializer]
 ;
 /// 6.7.1
 storage_class_specifier:
@@ -183,7 +183,7 @@ specifier_qualifier_list:
 ;
 /// 6.7.2.1
 struct_declarator_list:
-  struct_declarator (',' gnu_attributes struct_declarator)* @
+  struct_declarator (',' gnu_attributes struct_declarator)*
 ;
 /// 6.7.2.1
 struct_declarator:
@@ -202,7 +202,7 @@ typeof_specifier:
 ;
 /// 6.7.2.2
 enumerator_list:
-  enumerator (?1 ',' enumerator)* @
+  enumerator (?1 ',' enumerator)*
 ;
 /// 6.7.2.2
 enumerator:
@@ -250,15 +250,15 @@ parameter_type_list:
 ;
 /// 6.7.6
 parameter_list:
-  parameter_declaration (?1 ',' parameter_declaration)* @
+  parameter_declaration (?1 ',' parameter_declaration)*
 ;
 /// 6.7.6
 parameter_declaration:
   declaration_specifiers [?1 declarator | abstract_declarator] gnu_attributes
 ;
 /// 6.7.6
 identifier_list:
-  Identifier (',' Identifier)* @
+  Identifier (',' Identifier)*
 ;
 /// 6.7.7
 type_name:
@@ -313,7 +313,7 @@ static_assert_declaration:
 // A.2.3 Statements
 
 /// 6.8
-statement:
+statement^:
   ?1 labeled_statement
 | compound_statement
 | expression_statement
@@ -341,7 +341,7 @@ compound_statement:
   '{' #1 block_item* #2 '}'
 ;
 /// 6.8.2
-block_item:
+block_item^:
   ?1 declaration | statement
 ;
 /// 6.8.3
@@ -422,14 +422,14 @@ declaration_list:
 
 
 // GNU attribute extension
-gnu_attributes:
-  (?1 gnu_attribute)*
+gnu_attributes^:
+  [?1 (?1 gnu_attribute)+ >]
 ;
 gnu_attribute:
   '__attribute__' '(' '(' attribute_list ')' ')'
 ;
 attribute_list:
-  attrib (',' attrib)* @
+  attrib (',' attrib)*
 ;
 attrib:
   [attrib_name ['(' [?1 Identifier [',' constant_expr (',' constant_expr)*] | argument_expression_list] ')']]

examples/c/src/parser.rs

@@ -672,7 +672,7 @@ impl<'a> PredicatesAndActions for Parser<'a> {
     }
     fn predicate_cast_expr_1(&self) -> bool {
         if self.is_parenthesized_type() {
-            // check this is not a compund literal
+            // check this is not a compound literal
             let mut it = self.cst.tokens[self.pos..].iter().skip(1);
             let mut paren_depth = 1;
             loop {

examples/calc/src/calc.llw

@@ -1,18 +1,18 @@
 token Num='<number>';
-token Plus='+' Minus='-' Star='*' Slash='/';
+token Plus='+' Minus='-' Star='*' Slash='/' Pow='^';
 token LPar='(' RPar=')';
 token Whitespace;
 
 skip Whitespace;
-
+right '^';
 start calc;
 
-calc: expr;
+calc^: expr;
 expr:
-  expr ('*' | '/') expr
-| expr ('+' | '-') expr
-| atomic
+  expr '^' expr @binary_expr
+| expr ('*' | '/') expr @binary_expr
+| expr ('+' | '-') expr @binary_expr
+| ('-' | '+') expr @unary_expr
+| Num @literal_expr
+| '(' expr ')' @paren_expr
 ;
-atomic: literal | paren;
-literal: Num;
-paren: '(' expr ')';

examples/calc/src/parser.rs

@@ -37,6 +37,8 @@ pub enum Token {
     Whitespace,
     #[regex(r"[0-9]+(\.[0-9]+)?")]
     Num,
+    #[token("^")]
+    Pow,
     #[token("+")]
     Plus,
     #[token("-")]
@@ -49,7 +51,7 @@ pub enum Token {
     LPar,
     #[token(")")]
     RPar,
-    #[regex(r"[^0-9 \t\n\f\+\-\*/\(\)]+", |_| false)]
+    #[regex(r"[^0-9 \t\n\f\+\-\*/\(\)^]+", |_| false)]
     Error,
 }
 

examples/json/src/json.llw

@@ -8,7 +8,7 @@ skip Whitespace;
 start file;
 
 file: value;
-value:
+value^:
   object
 | array
 | literal

examples/l/src/l.llw

@@ -14,28 +14,21 @@ param_list: '(' [param (?1 ',' param)* [',']] ')';
 param: Name ':' type_expr;
 type_expr: Name;
 block: '{' stmt* '}';
-stmt:
+stmt^:
   stmt_expr
 | stmt_let
-| block
 | stmt_return
 ;
 stmt_expr: expr ';';
 stmt_let: 'let' Name '=' expr ';';
 stmt_return: 'return' [expr] ';';
-expr: expr_bin;
-expr_bin:
-  expr_bin ('*' | '/') expr_bin
-| expr_bin ('+' | '-') expr_bin
-| expr_call
+expr:
+  expr ('*' | '/') expr @expr_binary
+| expr ('+' | '-') expr @expr_binary
+| expr arg_list @expr_call
+| Name @expr_name
+| '(' expr ')' @expr_paren
+| expr_literal ^
 ;
-expr_call:
-  expr_call arg_list
-| expr_literal
-| expr_name
-| expr_paren
-;
-arg_list: '(' [expr (?1 ',' expr)* [',']] ')';
 expr_literal: Int | 'true' | 'false';
-expr_name: Name;
-expr_paren: '(' expr ')';
+arg_list: '(' [expr (?1 ',' expr)* [',']] ')';

examples/l/tests/data/incomplete.tree

@@ -27,7 +27,7 @@ File [0..42]
                 Whitespace " " [23..24]
                 Asn "=" [24..25]
                 Whitespace " " [25..26]
-                ExprBin [26..29]
+                ExprBinary [26..29]
                     ExprLiteral [26..27]
                         Int "2" [26..27]
                         Whitespace " " [27..28]

examples/lua/src/lua.llw

@@ -20,7 +20,7 @@ start chunk;
 
 chunk: block;
 block: stat* [retstat];
-stat:
+stat^:
   emptystat
 | expstat
 | label
@@ -36,7 +36,7 @@ stat:
 ;
 emptystat: ';';
 /// superset of official grammar, check in cst that syntax is valid
-expstat: prefixexp [(',' prefixexp)* '=' explist @assignstat] @;
+expstat: prefixexp [(',' prefixexp)* '=' explist @assignstat];
 
 breakstat: 'break';
 gotostat: 'goto' Name;
@@ -60,16 +60,16 @@ localstat:
   | attnamelist ['=' explist]
   )
 ;
-attnamelist: Name attrib (',' Name attrib)*;
-attrib: ['<' Name '>'];
+attnamelist: Name [attrib] (',' Name [attrib])*;
+attrib: '<' Name '>';
 retstat: 'return' [explist] [';'];
 label: '::' Name '::';
 funcname: Name ('.' Name)* [':' Name];
-namelist: Name (',' Name)* @;
-explist: exp (',' exp)* @;
+namelist: Name (',' Name)*;
+explist: exp (',' exp)*;
 args_explist: '(' [exp (',' exp)*] ')'; // extra rule for better error handling
 
-exp: binexp;
+exp^: binexp;
 binexp:
   binexp ('*' | '/' | '//' | '%') binexp
 | binexp ('+' | '-') binexp
@@ -81,14 +81,14 @@ binexp:
 | binexp ('<' | '>' | '<=' | '>=' | '~=' | '==') binexp
 | binexp 'and' binexp
 | binexp 'or' binexp
-| unaryexp
+| unaryexp ^
 ;
 unaryexp:
   ('not' | '-' | '#' | '~') unaryexp
-| powexp
+| powexp ^
 ;
-powexp:
-  (literalexp | prefixexp | tableconstructor | functiondef) ['^' unaryexp]
+powexp^:
+  (literalexp | prefixexp | tableconstructor | functiondef) ['^' unaryexp >]
 ;
 literalexp:
   'nil'
@@ -104,10 +104,10 @@ prefixexp:
   prefixexp '[' exp ']' @indexexp
 | prefixexp '.' Name @fieldexp
 | ?1 prefixexp (args | ':' Name args) @callexp // resolve ambiguity described in section 3.3.1
-| nameexp
-| parenexp
+| nameexp ^
+| parenexp ^
 ;
-args:
+args^:
   args_explist
 | tableconstructor
 | stringarg

examples/oberon0/src/oberon0.llw

@@ -15,22 +15,22 @@ skip Comment Whitespace;
 start module;
 
 selector:
-  ('.' Ident | '[' expression ']')*
+  ('.' Ident | '[' expression ']')+
 ;
 factor:
-  Ident selector | Number | '(' expression ')' | '~' factor
+  Ident [selector] | Number | '(' expression ')' | '~' factor
 ;
-term:
-  factor (('*' | 'DIV' | 'MOD' | '&') factor)*
+term^:
+  factor [(('*' | 'DIV' | 'MOD' | '&') factor)+ >]
 ;
 simple_expression:
   ['+' | '-'] term (('+' | '-' | 'OR') term)*
 ;
-expression:
-  simple_expression [('=' | '#' | '<' | '<=' | '>' | '>=') simple_expression]
+expression^:
+  simple_expression [('=' | '#' | '<' | '<=' | '>' | '>=') simple_expression >]
 ;
 assignment_or_procedure_call:
-  Ident selector (':=' expression @assignment | [actual_parameters] @procedure_call)
+  Ident [selector] (':=' expression @assignment | [actual_parameters] @procedure_call)
 ;
 actual_parameters: '(' [expression (',' expression)*] ')';
 if_statement:
@@ -44,7 +44,7 @@ while_statement:
 repeat_statement:
   'REPEAT' statement_sequence 'UNTIL' expression
 ;
-statement:
+statement^:
   [assignment_or_procedure_call | if_statement | while_statement | repeat_statement]
 ;
 statement_sequence: statement (';' statement)*;

examples/oberon0/tests/data/incomplete.diag

@@ -1,4 +1,4 @@
-error: invalid syntax, expected one of: '+', '&', ',', 'DIV', 'DO', 'ELSE', 'ELSIF', 'END', '=', '>=', '>', '#', '<=', '<', 'MOD', '*', 'OF', 'OR', ']', ')', ';', '-', 'THEN', 'UNTIL'
+error: invalid syntax, expected one of: '+', '&', ',', 'DIV', 'DO', '.', 'ELSE', 'ELSIF', 'END', '=', '>=', '>', '#', '[', '<=', '<', 'MOD', '*', 'OF', 'OR', ']', ')', ';', '-', 'THEN', 'UNTIL'
   ┌─ <input>:6:7
   │
 6 │     x := 2 +