From be4957ee599e7e14c934e61f3d91354760b38acd Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Sun, 21 Jul 2024 16:15:17 +0200
Subject: Initial commit

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 README | 37 +++++++++++++++++++++++++++++++++++++
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 create mode 100644 README

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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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