38 lines
976 B
Plaintext
38 lines
976 B
Plaintext
# Elna programming language
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Elna compiles simple mathematical operations to machine code.
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The compiled program returns the result of the operation.
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## File extension
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.elna
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## Grammar PL/0
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program = block "." ;
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block = [ "const" ident "=" number {"," ident "=" number} ";"]
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[ "var" ident {"," ident} ";"]
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{ "procedure" ident ";" block ";" } statement ;
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statement = [ ident ":=" expression | "call" ident
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| "?" ident | "!" expression
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| "begin" statement {";" statement } "end"
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| "if" condition "then" statement
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| "while" condition "do" statement ];
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condition = "odd" expression |
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expression ("="|"#"|"<"|"<="|">"|">=") expression ;
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expression = [ "+"|"-"] term { ("+"|"-") term};
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term = factor {("*"|"/") factor};
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factor = ident | number | "(" expression ")";
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## Operations
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"!" - Write a line.
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"?" - Read user input.
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"odd" - The only function, returns whether a number is odd.
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