uploaded pixel grammar

Pixel Grammar/Pixel Grammar.txt

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+/**
+ * Copyright 2011 Roger Câmara
+ *  
+ * Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+
+ */
+
+
+"Start Symbol" = <Def>
+
+{ID Head}      = {Letter} + [_]
+{ID Tail}      = {Alphanumeric} + [_]
+{String Chars} = {Printable} + {HT} - ["]
+
+Identifier    = {ID Head}{ID Tail}*
+StringLiteral = '"' {String Chars}* '"'
+IntegerLiteral = {Digit}+
+RealLiteral = {Digit}+.{Digit}+
+
+! The grammar starts below
+<Def> ::= '(' 'def' Identifier '[' <ArgLi> ']' <CommandLi> ')'
+
+<ArgLi> ::= <Arg> <ArgLi> | 
+
+<Arg> ::= '(' <Type> Identifier ')'
+
+<Type> ::= 'int' | 'real' | 'str'
+
+<CommandLi> ::= <Command> <CommandLi> |
+
+<Command> ::= '(' <InnerCommand> ')'
+
+<InnerCommand> ::= <Decl> | <Atrib> | <Read> | <Print> | <If> | <While> | <CommandLi>
+
+<Decl> ::= <Type> <IdLi>
+
+<IdLi> ::= Identifier <IdLi2>
+
+<IdLi2> ::= Identifier <IdLi2> |
+
+<Atrib> ::= '=' Identifier <AritExpr>
+
+<AritExpr> ::= <Operan> | '(' <OpArit> <AritExpr> <AritExpr> ')'
+
+<Operan> ::= Identifier | LiteralString | LiteralInteger | LiteralReal
+
+<OpArit> ::= '+' | '-' | '*' | '/' | '&'
+
+<Read> ::= 'read' Identifier
+
+<Print> ::= 'print' <Operan>
+
+<If> ::= 'if' <ExprCond> <Command> <Else>
+
+<Else> ::= <Command> |
+
+<CondExpr> ::= '(' <OpCond> <Operan> <Operan> ')'
+
+<CondOp> ::= '>' |'<' | '<=' | '>=' | '==' | '!='
+
+<While> ::= 'while' <CondExpr> <CommandLi>