GRAMMAR.md

ERA COMPILER GRAMMAR

Represents the grammar for the ERA system-level programming language.

• Program : { Annotations | Data | Module | Code | Structure | Routine }
• Annotations : pragma PragmaDeclaration { PragmaDeclaration } end
• Data : data Identifier Literal { Literal } end
• Module : module Identifier { VarDeclaration | Routine | Structure } end
• Code : code { Statement } end
• Structure : struct Identifier { VarDeclaration } end

---

• PragmaDeclaration : Identifier ( [ " Text " ] )
• VarDeclaration : Type ( Variable | Array | Constant )
• Variable : VarDefinition { , VarDefinition } ;
• Constant : const ConstDefinition { , ConstDefinition } ;
• Array : [] ArrDefinition { , ArrDefinition } ;
• VarDefinition : Identifier [ := Expression ]
• ConstDefinition : Identifier := Expression
• ArrDefinition : Identifier [ Expression ]
• Type : ( int | short | byte [ @ ] ) | Identifier

---

• Routine : routine Identifier ( [ Parameters ] ) [ : Type ] RoutineBody
• Parameters : Parameter { , Parameter }
• Parameter : Type Identifier
• RoutineBody : do { Statement } end
• Statement : [ Label ] ( AssemblyBlock | ExtensionStatement )
• Label : < Identifier >

---

• AssemblyBlock: asm AssemblyStatement ; { AssemblyStatement ; } end
• AssemblyStatement
   : skip // NOP
   | stop // STOP
   | < Identifier > // Label
   | format ( 8 | 16 | 32 ) // format of next command
   | Register := -> Register
   | -> Register := Register
   | Register := Register
   | Register := Identifier // Label
   | Register := Expression // Should be in range [0-31]
   | Register := Register + Expression
   | Register += Register
   | Register -= Register
   | Register >>= Register
   | Register <<= Register
   | Register |= Register
   | Register &= Register
   | Register ^= Register
   | Register <= Register
   | Register >= Register
   | Register ?= Register
   | if Register goto Register
• Register : R0 | R1 | ... | R30 | R31

---

• ExtensionStatement : Assignment | Swap | ( Call ; ) | If | Loop | Break | Return | VarDeclaration
• Loop : For | While | LoopWhile
• For : for Identifier [ from Expression ] [ to Expression] [ step Expression ] LoopBody end
• While : while Expression LoopBody end
• LoopWhile : LoopBody while Expression end
• LoopBody : loop BlockBody
• BlockBody : { Statement }
• Break : break ;
• Return : return [ ( Expression | Call ) ] ;
• Assignment : Receiver := Expression ;
• Swap : Reveiver <=> Receiver ;
• Print : print Expression ;

---

• If : if Expression do BlockBody ( end | else BlockBody end )
• Call : Identifier CallArgs
• CallArgs : ( [ Expression { , Expression } ] )

---

• Expression : Operand { Operator Operand }
• Operator : + | - | * | & | | | ^ | ? | = | /= | < | > | >= | <=
• Operand : Primary | Register | Dereference | Reference | Literal | ( Expression )
• Receiver : Primary | Dereference | Register
• Primary : Identifier { . Identifier } [ ArrayAccess | CallArgs ]
• ArrayAccess : [ Expression ]
• Reference : <- Primary
• Dereference : -> [ Expression ]

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• Identifier : (_a-zA-Z0-9)+
• Literal: [ - ] (0-9)+
• Text: (\,\.\-_a-zA-Z0-9)+

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