Some fixes to the EBNF grammar
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greg
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6b47ecf2d7
commit
dfbd951aaf
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@ -3,8 +3,10 @@
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//!
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//!
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//! # Schala EBNF Grammar
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//! Terminal productions are in 'single quotes' or UPPERCASE if they are a class of tokens,
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//! or otherwise not representable in ASCII.
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//! This document is the authoritative grammar of Schala, represented in something approximating
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//! Extended Backus-Naur form. Terminal productions are in "double quotes", or UPPERCASE
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//! if they represent a class of tokens rather than an specific string, or are otherwise
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//! unreprsentable in ASCII.
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//!
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//! ## Top level structure
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//!
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@ -15,7 +17,9 @@
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//! block := "{" (statement delimiter)* "}"
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//! declaration := type_declaration | func_declaration | binding_declaration | impl_declaration
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//! ```
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//! ## Declarations - Types
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//! ## Declarations
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//!
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//! ### Types
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//! ```
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//! type_declaration := "type" type_declaration_body
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//! type_declaration_body := "alias" type_alias | "mut"? type_singleton_name "=" type_body
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@ -25,7 +29,7 @@
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//! typed_identifier_list := typed_identifier*
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//! typed_identifier := IDENTIFIER type_anno
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//! ```
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//! ## Declaration - Functions
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//! ### Functions
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//!
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//! ```
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//! func_declaration := func_signature func_body
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@ -37,10 +41,10 @@
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//! formal_param := IDENTIFIER type_anno+
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//! ```
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//!
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//! ## Declaration - Variable bindings
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//! ### Variable bindings
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//! ```binding_declaration := "let" "mut"? IDENTIFIER "=" expresion```
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//!
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//! ## Declaration - Interface
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//! ### Interfaces
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//!
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//! ```
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//! interface_declaration := "interface" type_singleton_name signature_block
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@ -49,10 +53,10 @@
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//! signature_block := "{" (func_signature)* "}"
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//! ```
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//!
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//! ## Type Annotations
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//! ### Type Annotations
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//!
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//! ```
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//! type_anno := (":" type_name)+
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//! type_anno := ":" type_name
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//! type_name := type_singleton_name | "(" type_names ")"
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//! type_names := ε | type_name (, type_name)*
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//! type_singleton_name = IDENTIFIER (type_params)*
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@ -66,26 +70,24 @@
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//! prefix_expr := prefix_op call_expr
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//! prefix_op := "+" | "-" | "!" | "~"
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//! call_expr := index_expr ( "(" expr_list ")" )* | ε
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//! ```
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//!
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//! ```
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//! expr_list := expression ("," expression)* | ε
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//! index_expr := primary ( "[" (expression ("," (expression)* | ε) "]" )*
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//! primary := literal | paren_expr | if_expr | for_expr | while_expr | identifier_expr | lambda_expr | anonymous_struct | list_expr
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//! expr_or_block := "{" (statement delimiter)* "}" | expr
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//! ```
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//!
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//! ## Primary expressions
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//! ### Primary expressions
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//!
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//! ```
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//! list_expr := "[" (expression, ",")* "]"
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//! lambda_expr := "\\" lambda_param_list type_anno+ nonempty_func_body
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//! lambda_expr := "\" lambda_param_list type_anno+ nonempty_func_body
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//! lambda_param_list := formal_param_list | formal_param
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//! paren_expr := LParen paren_inner RParen
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//! paren_inner := (expression ",")*
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//! identifier_expr := named_struct | IDENTIFIER
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//! ```
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//!
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//! Expression literals
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//! ## Literals
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//! ```
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//! literal := "true" | "false" | number_literal | STR_LITERAL
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//! named_struct := IDENTIFIER record_block
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@ -102,7 +104,7 @@
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//! digits := (DIGIT_GROUP underscore)+
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//! ```
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//!
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//! ## Patterns
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//! ### Patterns
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//! ```
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//! pattern := "(" (pattern, ",")* ")" | simple_pattern
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//! simple_pattern := pattern_literal | record_pattern | tuple_struct_pattern
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@ -113,11 +115,7 @@
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//! tuple_struct_pattern := IDENTIFIER "(" (pattern, ",")* ")"
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//! ```
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//!
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//! ```
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//! expr_or_block := "{" (statement delimiter)* "}" | expr
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//! ```
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//!
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//! ## If-expressions
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//! ### If-expressions
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//! ```
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//! if_expr := "if" discriminator ("then" condititional | "is" simple_pattern_match | guard_block)
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//! discriminator := precedence_expr (operator)+
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@ -129,7 +127,7 @@
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//! guard := "is" pattern | (operator)+ precedence_expr
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//! ```
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//!
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//! ## While expressions
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//! ### While expressions
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//! ```
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//! while_expr := "while" while_cond "{" (statement delimiter)* "}"
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//! while_cond := ε | expression | expression "is" pattern //TODO maybe is-expresions should be primary
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@ -137,7 +135,7 @@
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//!
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//! //TODO this implies there must be at least one enumerator, which the parser doesn"t support right
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//! //this second, and maybe should fail later anyway
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//! ## For-expressions
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//! ### For-expressions
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//! ```
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//! for_expr := "for" (enumerator | "{" enumerators "}") for_expr_body
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//! for_expr_body := "return" expression | "{" (statement delimiter)* "}"
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