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Some fixes to the EBNF grammar

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This commit is contained in:
greg 2019-06-09 01:08:32 -07:00
parent 6b47ecf2d7
commit dfbd951aaf
1 changed files with 35 additions and 37 deletions
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72
schala-lang/language/src/parsing.rs
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@ -3,8 +3,10 @@
//!
//!
//! # Schala EBNF Grammar
//! Terminal productions are in 'single quotes' or UPPERCASE if they are a class of tokens,
//! or otherwise not representable in ASCII.
//! This document is the authoritative grammar of Schala, represented in something approximating
//! Extended Backus-Naur form. Terminal productions are in "double quotes", or UPPERCASE
//! if they represent a class of tokens rather than an specific string, or are otherwise
//! unreprsentable in ASCII.
//!
//! ## Top level structure
//!
@ -15,7 +17,9 @@
//! block := "{" (statement delimiter)* "}"
//! declaration := type_declaration | func_declaration | binding_declaration | impl_declaration
//! ```
//! ## Declarations - Types
//! ## Declarations
//!
//! ### Types
//! ```
//! type_declaration := "type" type_declaration_body
//! type_declaration_body := "alias" type_alias | "mut"? type_singleton_name "=" type_body
@ -25,8 +29,8 @@
//! typed_identifier_list := typed_identifier*
//! typed_identifier := IDENTIFIER type_anno
//! ```
//! ## Declaration - Functions
//!
//! ### Functions
//!
//! ```
//! func_declaration := func_signature func_body
//! func_body := ε | nonempty_func_body
@ -36,29 +40,29 @@
//! formal_param_list := "(" (formal_param ",")* ")"
//! formal_param := IDENTIFIER type_anno+
//! ```
//!
//! ## Declaration - Variable bindings
//!
//! ### Variable bindings
//! ```binding_declaration := "let" "mut"? IDENTIFIER "=" expresion```
//!
//! ## Declaration - Interface
//!
//!
//! ### Interfaces
//!
//! ```
//! interface_declaration := "interface" type_singleton_name signature_block
//! impl_declaration := "impl" type_singleton_name decl_block | "impl" type_singleton_name "for" type_name decl_block
//! decl_block := "{" (func_declaration)* "}"
//! signature_block := "{" (func_signature)* "}"
//! ```
//!
//! ## Type Annotations
//!
//!
//! ### Type Annotations
//!
//! ```
//! type_anno := (":" type_name)+
//! type_anno := ":" type_name
//! type_name := type_singleton_name | "(" type_names ")"
//! type_names := ε | type_name (, type_name)*
//! type_singleton_name = IDENTIFIER (type_params)*
//! type_params := "<" type_name (, type_name)* ">"
//! ```
//!
//!
//! ## Expressions
//! ```
//! expression := precedence_expr type_anno+
@ -66,26 +70,24 @@
//! prefix_expr := prefix_op call_expr
//! prefix_op := "+" | "-" | "!" | "~"
//! call_expr := index_expr ( "(" expr_list ")" )* | ε
//! ```
//!
//! ```
//! expr_list := expression ("," expression)* | ε
//! index_expr := primary ( "[" (expression ("," (expression)* | ε) "]" )*
//! primary := literal | paren_expr | if_expr | for_expr | while_expr | identifier_expr | lambda_expr | anonymous_struct | list_expr
//! expr_or_block := "{" (statement delimiter)* "}" | expr
//! ```
//!
//! ## Primary expressions
//!
//!
//! ### Primary expressions
//!
//! ```
//! list_expr := "[" (expression, ",")* "]"
//! lambda_expr := "\\" lambda_param_list type_anno+ nonempty_func_body
//! lambda_expr := "\" lambda_param_list type_anno+ nonempty_func_body
//! lambda_param_list := formal_param_list | formal_param
//! paren_expr := LParen paren_inner RParen
//! paren_inner := (expression ",")*
//! identifier_expr := named_struct | IDENTIFIER
//! ```
//!
//! Expression literals
//!
//! ## Literals
//! ```
//! literal := "true" | "false" | number_literal | STR_LITERAL
//! named_struct := IDENTIFIER record_block
@ -93,7 +95,7 @@
//! record_entry := IDENTIFIER ":" expression
//! anonymous_struct := TODO
//! ```
//!
//!
//! A `float_literal` can still be assigned to an int in type-checking
//! ```
//! number_literal := int_literal | float_literal
@ -101,8 +103,8 @@
//! float_literal := digits ("." digits)
//! digits := (DIGIT_GROUP underscore)+
//! ```
//!
//! ## Patterns
//!
//! ### Patterns
//! ```
//! pattern := "(" (pattern, ",")* ")" | simple_pattern
//! simple_pattern := pattern_literal | record_pattern | tuple_struct_pattern
@ -112,12 +114,8 @@
//! record_pattern_entry := IDENTIFIER | IDENTIFIER ":" Pattern
//! tuple_struct_pattern := IDENTIFIER "(" (pattern, ",")* ")"
//! ```
//!
//! ```
//! expr_or_block := "{" (statement delimiter)* "}" | expr
//! ```
//!
//! ## If-expressions
//!
//! ### If-expressions
//! ```
//! if_expr := "if" discriminator ("then" condititional | "is" simple_pattern_match | guard_block)
//! discriminator := precedence_expr (operator)+
@ -128,16 +126,16 @@
//! guard_arm := guard "->" expr_or_block
//! guard := "is" pattern | (operator)+ precedence_expr
//! ```
//!
//! ## While expressions
//!
//! ### While expressions
//! ```
//! while_expr := "while" while_cond "{" (statement delimiter)* "}"
//! while_cond := ε | expression | expression "is" pattern //TODO maybe is-expresions should be primary
//! ```
//!
//!
//! //TODO this implies there must be at least one enumerator, which the parser doesn"t support right
//! //this second, and maybe should fail later anyway
//! ## For-expressions
//! ### For-expressions
//! ```
//! for_expr := "for" (enumerator | "{" enumerators "}") for_expr_body
//! for_expr_body := "return" expression | "{" (statement delimiter)* "}"