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