Listing: fcall.pb

; fcall.pb
IncludeFile "..\base2.pb"
IncludeFile "..\labels.pb"
IncludeFile "..\symboltable.pb"


Procedure.s VarRef(*V.SVariable)
  Select *V\RefKind
    Case #Ref_Global
      ProcedureReturn "[v_" + *V\Name + "]"
    Default
      Error("Unknown variable scope kind")
  EndSelect
EndProcedure

; Return the asm for accessing the value of a variable
Procedure.s VarValue(Name.s)
  Protected *V.SSymbol = LookupSymbol(Name)
  If *V And *V\Kind = #SKind_Variable
    ProcedureReturn VarRef(*V)
  Else
    Error("Undeclared variable: " + Name)
  EndIf
EndProcedure

Procedure FunctionCall(Name.s)
  *V.SFunction = LookupSymbolNoScopeResolve(Name)
  If *V And *v\Kind = #SKind_Function
    Emit("call " + *v\Ref)
  Else
    Error("Undeclared function: " + Name)
  EndIf
EndProcedure

Procedure Value()
  ; value  ::= <integer> | <variable> | <fcall()> | '(' <expression> ')'
  Protected Name.s
  If IsDigit(Look)
    Emit("mov  eax, " + GetInteger())
  ElseIf IsAlpha(Look)
    Name = GetName()
    If Look = '('
      Match('(')
      FunctionCall(Name)
      Match(')')
    Else
      Emit("mov  eax, " + VarValue(Name))
    EndIf
  Else
    Expected("value")
  EndIf
EndProcedure

Procedure Expression()
  ; expression ::= <value>
  Value()
EndProcedure

Procedure Assignment(Name.s)
  ; assignment ::= <name> = <expression>
  MatchWhite('=')
  Expression()
  Emit2("mov  ", VarValue(Name), "eax")
EndProcedure

Procedure VariableDeclaration()
  ; vardecl ::= var <name> as <type>
  Protected Name.s
  Protected TypeS.s, TypeI.i
  Protected *V.SVariable
  
  ; Get name and type
  Name = GetName()
  If GetName() <> "as"
    Expected("as")
  EndIf
  TypeS = GetName()
  
  AddVariable(Name, TypeS, #Ref_Global, 0)
EndProcedure


Procedure Statement()
  Protected N.s
  N = GetName()
  If Look = '('
    Match('(')
    FunctionCall(N)
    Match(')')
  Else
    Select N
      Case "var": VariableDeclaration()
      Default:    Assignment(N)
    EndSelect
  EndIf
EndProcedure

Procedure Program()
  ; program    ::= { <assignment> }
  EatWhiteNewlines()
  While Look
    Statement()
    EatWhiteNewlines()
  Wend
EndProcedure

Procedure GlobalAsmDefinition(ScopedName.s, *V.SVariable)
  If *V\Kind = #SKind_Variable
    If *V\RefKind = #Ref_Global
      Emit("v_" + *v\Name + " dd 0")
    EndIf
  EndIf
EndProcedure

Procedure Footer()
  Emit("push 0")
  Emit("call _ExitProcess")
  Emit("; Global variables: ")
  EnumerateSymbols(@GlobalAsmDefinition())
EndProcedure

; Add a few functions to the symbol table so we can call them
*F.SFunction = AddFunction("MyFunc")
*F\Type = #TyLong

*F.SFunction = AddFunction("DoCoolStuff")
*F\Type = #TyLong


InitMulti()
Program()
Footer()
Input()