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Some changes to EBNF grammar

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greg 2017-09-17 00:04:27 -07:00
parent 20c74953b5
commit 8be757beca
1 changed files with 37 additions and 13 deletions
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50
src/schala_lang/parsing.rs
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@ -277,26 +277,50 @@ op := '+', '-', etc.
*/
/* for reference, here is the scala EBNF for expressions:
* see http://scala-lang.org/files/archive/spec/2.12/06-expressions.html
Expr ::= (Bindings | id | ‘_’) ‘=>’ Expr
| Expr1
Expr1 ::= ‘if’ ‘(’ Expr ‘)’ {nl} Expr [[semi] else Expr]
| ‘while’ ‘(’ Expr ‘)’ {nl} Expr
| ‘try’ ‘{’ Block ‘}’ [‘catch’ ‘{’ CaseClauses ‘}’]
[‘finally’ Expr]
| ‘do’ Expr [semi] ‘while’ ‘(’ Expr ’)’
| ‘for’ (‘(’ Enumerators ‘)’ | ‘{’ Enumerators ‘}’)
{nl} [‘yield’] Expr
| ‘throw’ Expr
| ‘return’ [Expr]
| [SimpleExpr ‘.’] id ‘=’ Expr
| SimpleExpr1 ArgumentExprs ‘=’ Expr
| PostfixExpr
| PostfixExpr Ascription
| PostfixExpr ‘match’ ‘{’ CaseClauses ‘}’
PrefixExpr ::= [‘-’ | ‘+’ | ‘~’ | ‘!’] SimpleExpr
*/
/* Schala EBNF Grammar */
/* Terminal productions are «in Guillemets» or UPPERCASE if they are a class
/* Terminal productions are in 'single quotes' or UPPERCASE if they are a class
* or not representable in ASCII
program := (statement delimiter)* EOF
delimiter := NEWLINE | «;»
delimiter := NEWLINE | ';'
statement := expression | declaration
declaration := type_alias | type_declaration | func_declaration
type_alias := «alias» IDENTIFIER «=» IDENTIFIER
type_declaration := «type» IDENTIFIER «=» type_body
type_body := variant_specifier («|» variant_specifier)*
variant_specifier := «{» member_list «}»
type_alias := 'alias' IDENTIFIER '=' IDENTIFIER
type_declaration := 'type' IDENTIFIER '=' type_body
type_body := variant_specifier ('|' variant_specifier)*
variant_specifier := '{' member_list '}'
member_list := (IDENTIFIER type_anno)*
func_declaration := «fn» IDENTIFIER «(» param_list «)»
param_list := (IDENTIFIER type_anno+ «,»)*
func_declaration := 'fn' IDENTIFIER '(' param_list ')'
param_list := (IDENTIFIER type_anno+ ',')*
type_anno := «:» type
type_anno := ':' type
expression := precedence_expr
precedence_expr := primary
@ -304,11 +328,11 @@ primary := literal | paren_expr | identifier_expr
paren_expr := LParen expression RParen
identifier_expr := call_expr | index_expr | IDENTIFIER
literal := «true» | «false» | number_literal | STR_LITERAL
literal := 'true' | 'false' | number_literal | STR_LITERAL
call_expr := IDENTIFIER «(» expr_list «)» //TODO maybe make this optional? or no, have a bare identifier meant to be used as method taken care of in eval
index_expr := «[» (expression («,» (expression)* | ε) «]»
expr_list := expression («,» expression)* | ε
call_expr := IDENTIFIER '(' expr_list ')' //TODO maybe make this optional? or no, have a bare identifier meant to be used as method taken care of in eval
index_expr := '[' (expression (',' (expression)* | ε) ']'
expr_list := expression (',' expression)* | ε
// a float_literal can still be assigned to an int in type-checking
number_literal := int_literal | float_literal