77 lines
2.3 KiB
Markdown
77 lines
2.3 KiB
Markdown
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玩具語言的 BNF 文法
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===================
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```
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lines = line | line ; lines
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line = expression | value_assignment | function_assignment | type_definition | jump_statment
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```
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expression
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------------
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```
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expression = term | term {+ -} expression
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term = factor | factor {* /} term
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# paren_exp = parenthesis_expression
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factor = list_unit | function(factor_list)
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factor_list = factor | factor , factor_list
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function = factor | lambda (lambda_inputs){lines}
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lambda_inputs = "" | lambda_input_pair | lambda_input_pair, lambda_inputs
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lambda_input_pair = lambda_input_type identifier
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lambda_input_type = non_function_type | simple_function_type
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list_unit = list_ref | { list_items }
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list_items = list_ref | list_ref , list_items
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list_ref = paren_exp | list_unit [ paren_exp ]
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paren_exp = compound_identifier | const | ( expression )
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compound_identifier = identifier | identifier . identifier
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const = number | bool | string
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number = float_num | integer
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string = " string_content "
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```
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type definition
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--------------------
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```
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type_definition = typedef identifier = type
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type = non_function_type | function_type
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non_function_type = struct_type | array_type | union_type | simple_type
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simple_type = int | float | bool | char | void
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# struct {foo: int, bar: bool}
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struct_type = struct {struct_items}
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struct_items = struct_item | struct_item , struct_items
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struct_item = type identifier
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list_type = list ( type )
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union_type = union ( types )
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types = type | type , types
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function_type = simple_function_type | poly_function_type
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simple_function_type = paren_types -> paren_type
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paren_types = paren_type | paren_type , paren_types
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paren_type = type | ( paren_types )
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poly_function_type = forall identifier , poly_function_content
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poly_function_content = poly_paren_types -> poly_paren_type
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poly_paren_types = poly_paren_type | poly_paren_type , poly_paren_types
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poly_paren_type = type | identifier | ( poly_paren_type )
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```
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function assignment
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------------------
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```
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function_assignment
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function_type identifier = lambda (function_inputs){lines}
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function_inputs = identifier | identidier , identifiers
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```
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value assignment
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------------------
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```
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value_assignment = non_function_type identifier = expression
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```
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jump statement
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--------------------
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```
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jump_statement = return expression
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```
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