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Addition of loops in stdlambda #126

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Addition of loops in stdlambda #126

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abb2856
Addition of loops in stdlambda
Almesi May 21, 2025
95ed765
Merge branch 'sancarn:master' into master
Almesi May 21, 2025
f82d7ff
Update for loops and more
Almesi May 23, 2025
81dc1f4
Merge branch 'master' of https://github.com/Almesi/stdVBA
Almesi May 23, 2025
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226 changes: 219 additions & 7 deletions src/stdLambda.cls
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Original file line number Diff line number Diff line change
Expand Up @@ -147,6 +147,10 @@ Private Type TThis

UsePerformanceCache as Boolean
PerformanceCache as Object

ExitStackName() As String
ExitStackIndex() As Long
ExitStackSize As Long
End Type
Private This as TThis

Expand Down Expand Up @@ -411,6 +415,21 @@ Private Function getTokenDefinitions() As TokenDefinition()
i = i + 1: arr(i) = getTokenDefinition("then", "then", isKeyword:=True)
i = i + 1: arr(i) = getTokenDefinition("else", "else", isKeyword:=True)
i = i + 1: arr(i) = getTokenDefinition("end", "end", isKeyword:=True)

' Loops
i = i + 1: arr(i) = getTokenDefinition("for", "for", isKeyword:=True)
i = i + 1: arr(i) = getTokenDefinition("to", "to", isKeyword:=True)
i = i + 1: arr(i) = getTokenDefinition("step", "step", isKeyword:=True)
i = i + 1: arr(i) = getTokenDefinition("next", "next", isKeyword:=True)

i = i + 1: arr(i) = getTokenDefinition("do", "do", isKeyword:=True)
i = i + 1: arr(i) = getTokenDefinition("until", "until", isKeyword:=True)
i = i + 1: arr(i) = getTokenDefinition("while", "while", isKeyword:=True)
i = i + 1: arr(i) = getTokenDefinition("loop", "loop", isKeyword:=True)

i = i + 1: arr(i) = getTokenDefinition("exit", "exit", isKeyword:=True)


' Brackets
i = i + 1: arr(i) = getTokenDefinition("lBracket", "\(")
i = i + 1: arr(i) = getTokenDefinition("rBracket", "\)")
Expand Down Expand Up @@ -522,7 +541,9 @@ End Sub
'11. Arithmetic (^)
'12. Arithmetic (Unary +, -) (for RHS of power operator) e.g. 2^-1
'13. Flow (if then else)
'14. Value (numbers, $vars, strings, booleans, brackets)
'14. Do (do until while loop)
'15. For (for do step next)
'16. Value (numbers, $vars, strings, booleans, brackets)
'@remark - The order of priority is opposite to the order of evaluation. I.E. Comparrison is evaluated before Logical AND allowing
'expressions such as `1<2 and 2<3` to be evaluated correctly without requiring bracketing. It's important to note however that all
'comparrisons have the same priority. This means that `1<2<3` will be evaluated as `(1<2)<3` which is not the same as `1<(2<3)`.
Expand Down Expand Up @@ -590,7 +611,7 @@ Private Sub parseLogicPriority4() 'not
End If
End Sub

'Parse comparison operators (=, <>, <, <=, >, >=, is, Like)
'Parse comparison operators (=, <>, <, <=, >, >=, is, Like, =)
Private Sub parseComparisonPriority1()
Call parseArithmeticPriority1
Dim bLoop As Boolean: bLoop = True
Expand Down Expand Up @@ -738,7 +759,7 @@ Private Sub parseFlowPriority1()
this.stackSize = size

If optConsume("end") Then
Call addOperation(oPush, , 0, 1) 'Expressions should always return a value
' Why should it always return? I disabled it for now because in a loop it keeps pushing onto the stack Call addOperation(oPush, , 0, 1) 'Expressions should always return a value
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Removing this from this function has me very nervous. I'm not sure what the side effects would be of removing this.

In order to remove from the stack you can add your own cleanup in the loop. Either using iPop or iMerge.

this.operations(skipElseJumpIndex).value = this.iOperationIndex
Else
Call consume("else")
Expand All @@ -747,6 +768,120 @@ Private Sub parseFlowPriority1()

Call optConsume("end")
End If
Call consumeExit("if", This.iOperationIndex)
Else
Call parseFlowPriority2
End If
End Sub

'Parse loops (do ... until|while ... loop)
Private Sub parseFlowPriority2()
If optConsume("do") Then
' Do Until|While {Expr}
Dim RepeatLoop As Integer: RepeatLoop = This.iOperationIndex
Dim SkipLoop As Integer: SkipLoop = -1
If optConsume("until") Then
Call parseExpression
SkipLoop = addOperation(oJump, ifTrue, , -1)
ElseIf optConsume("while") Then
Call parseExpression
SkipLoop = addOperation(oJump, ifFalse, , -1)
Else
' Infinite loop as long as no exit do is used
End If

Call parseBlock("loop")
Call consume("loop")

' xxx
' Loop Until|While {expr}
If optConsume("until") Then
Call parseExpression
SkipLoop = addOperation(oJump, ifTrue, , -1)
ElseIf optConsume("while") Then
Call parseExpression
SkipLoop = addOperation(oJump, ifFalse, , -1)
Else
' Nothing happens
End If

' Loop back to start
Call addOperation(oJump, , RepeatLoop, -1)
Call consumeExit("do", This.iOperationIndex)
If SkipLoop > -1 Then This.operations(SkipLoop).value = This.iOperationIndex
Else
Call parseFlowPriority3
End If
End Sub

Private Sub parseFlowPriority3()
If optConsume("for") Then

' 1. let index = LowerBound
Dim varName As String: varName = consume("var")
Call consume("equal")
Call parseExpression
Dim IncrementIndex As Long: IncrementIndex = findVariable(varName)
If IncrementIndex >= 0 Then
' If the variable already existed, move the data to that pos on the stack
Call addOperation(oSet, , IncrementIndex, -1)
Else
' If the variable didn't exist yet, treat this stack pos as its source
Call this.scopes(this.scopeCount).add(varName, this.stackSize)
IncrementIndex = this.stackSize - 1
If IncrementIndex = 0 Then IncrementIndex = 1 ' Avoid referencing the current operation. | Used when the last added variable was declared in for loop
End If

' Index > UpperBound
' Jump if Condition true
Call addOperation(oAccess, , IncrementIndex, 1)
Dim RepeatLoop As Long: RepeatLoop = This.iOperationIndex - 1' beginning of loop (condition)
If peek("to") Then
This.iTokenIndex = This.iTokenIndex + 1
Else
Call parseBlock("to")
Call consume("to")
End If
Call parseStatement
Dim ConditionIndex As Long: ConditionIndex = addOperation(oComparison, oGt, , -1)
Dim SkipLoop As Integer : SkipLoop = addOperation(oJump, ifTrue, , -1) ' Skip loop

' Setup increment Values
Dim Increment As Long, Operator As ISubType, Condition As ISubType
If optConsume("step") Then
If peek("literalNumber") Then
Operator = oadd
Condition = oGt
Else
Select Case True
Case optConsume("add") : Operator = oadd : Condition = oGt
Case optConsume("subtract") : Operator = osubtract : Condition = oLt
Case optConsume("multiply") : Operator = omultiply : Condition = oGt
Case optConsume("divide") : Operator = odivide : Condition = oLt
Case optConsume("power") : Operator = opower : Condition = oGt
End Select
End If
Increment = CLng(consume("literalNumber")) ' TODO add more functionality than just numbers
Else
Increment = 1
Operator = oadd
Condition = oGt
End If

This.Operations(ConditionIndex).subType = Condition ' Changes compare-operator of condition according to "step"

' Get rest of loop
' Setup index-incrementation: let index = index Operator Increment
' Setup loop-repeat
Call parseBlock("next")
Call consume("next")
Call addOperation(oAccess , , IncrementIndex , -1)
Call addOperation(oPush , , Increment , -1)
Call addOperation(oArithmetic, Operator , , -1)
Call addOperation(oSet , , IncrementIndex , -1)
Call addOperation(oJump , , RepeatLoop , -1)
Call consumeExit("for", This.iOperationIndex)
This.Operations(SkipLoop).Value = This.iOperationIndex
Else
Call parseValuePriority1
End If
Expand Down Expand Up @@ -774,6 +909,10 @@ Private Sub parseValuePriority1()
Call parseFunction
End If
Call parseManyAccessors(iOperationType)
ElseIf peek("step") Then ' does nothing, so that parseflowPriority3 does its thing
ElseIf optConsume("exit") Then
Call addExit(this.tokens(this.iTokenIndex).Type.name)
this.iTokenIndex = this.iTokenIndex + 1
Else
Call consume("lBracket")
Call parseExpression
Expand Down Expand Up @@ -929,7 +1068,7 @@ Private Sub parseAssignment()
If offset >= 0 Then
' If the variable already existed, move the data to that pos on the stack
Call addOperation(oSet, , offset, -1)
Call addOperation(oAccess, , offset, 1) ' To keep a return value
'Call addOperation(oAccess, , offset, 1) ' To keep a return value
Else
' If the variable didn't exist yet, treat this stack pos as its source
Call this.scopes(this.scopeCount).add(varName, this.stackSize)
Expand Down Expand Up @@ -984,6 +1123,7 @@ Private Function parseFunctionAccess() As Boolean
' Add call and return data
Call addOperation(oJump, , funcPos, -iArgCount) 'only -argCount since pushing Result and popping return pos cancel out
this.operations(returnPosIndex).value = this.iOperationIndex
Call consumeExit("fun", This.iOperationIndex)
Else
this.iTokenIndex = this.iTokenIndex - 1 ' Revert token consumption
End If
Expand Down Expand Up @@ -1670,10 +1810,24 @@ Private Function getTokenDefinition(ByVal sName As String, ByVal sRegex As Strin
getTokenDefinition.RegexObj.ignoreCase = ignoreCase
End Function

'Used to get the definition of a token by name for inline-insertion of tokens
'@param {ByVal TokenDefinition()} The name of the token
'@param {ByVal String} The name of the token
'@returns {TokenDefinition} The definition of the token
Private Function getTokenDefinitionByName(ByRef tokenDefs() As TokenDefinition, ByVal tokenName As String) As TokenDefinition
Dim i As Long
For i = LBound(tokenDefs) To Ubound(tokenDefs)
If tokenDefs(i).Name = tokenName Then
getTokenDefinitionByName = tokenDefs(i)
Exit Function
End If
Next i
End Function

'Copies one variant to a destination
'@param {ByRef Token()} tokens Tokens to remove the specified type from
'@param {ByRef token()} tokens Tokens to remove the specified type from
'@param {string} sRemoveType Token type to remove.
'@returns {Token()} The modified token array.
'@returns {token()} The modified token array.
Private Function removeTokens(ByRef tokens() As token, ByVal sRemoveType As String) As token()
Dim iCountRemoved As Long: iCountRemoved = 0
Dim iToken As Long
Expand Down Expand Up @@ -1931,7 +2085,65 @@ Private Function ConcatArrays(ByVal Arr1 As Variant, ByVal Arr2 As Variant) As V
End If
End Function

'----------
'Handle exit-token
'----------

'pushes a value onto the exitstack and creates a jump operation
'@param {String} for what should be exited e.g. for, if, do, function
Private Sub addExit(ExitWhat As String)
With this
.ExitStackSize = .ExitStackSize + 1
ReDim Preserve .ExitStackName(1 To .ExitStackSize)
ReDim Preserve .ExitStackIndex(1 To .ExitStackSize)
.ExitStackName(.ExitStackSize) = ExitWhat
.ExitStackIndex(.ExitStackSize) = addOperation(oJump, , , -1)
End With
End Sub

'If Caller is equal to stackname of exit then it will get the jump-condition index of operations and give it a value
' This is important, as something like this is possible:
' let x = 0
' for i = 1 to 10
' if $1 = 10 then
' exit for-----------|
' else |
' {---} |
' do |
' if x = 10 then |
' exit do----|----|
' end | |
' x = x + 1 | |
' loop | |
' end-------------------|---/
' next |
' {---} <-----------------/

' The code might be several layers deep, to accomodate for that this exitstack was created
'@param {String} Name of the current calling abstraction e.g for, if, do, function
'@param {Long} Index where to jump to once exit is run
Private Sub consumeExit(Caller As String, JumpIndex As Long)
Dim i As Long
Dim TempName() As String
Dim TempIndex() As Long
With this
If .ExitStackSize = 0 Then Exit Sub
If .ExitStackName(.ExitStackSize) = Caller Then
.Operations(.ExitStackIndex(.ExitStackSize)).Value = JumpIndex
.ExitStackSize = ExitStackSize - 1
If .ExitStackSize > 0 Then
ReDim TempName(.ExitStackSize)
ReDim TempIndex(.ExitStackSize)
For i = 1 To .ExitStackSize
TempName(i) = this.ExitStackName(i)
TempIndex(i) = this.ExitStackIndex(i)
Next i
End If
.ExitStackName = TempName
.ExitStackIndex = TempIndex
End If
End With
End Sub

'----------
'evaluation Mac
Expand Down Expand Up @@ -2017,4 +2229,4 @@ macJmpCall:
Case 29: Call CopyVariant(macCallByName, CallByName(obj, funcName, callerType, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20, a21, a22, a23, a24, a25, a26, a27, a28))
Case 30: Call CopyVariant(macCallByName, CallByName(obj, funcName, callerType, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17, a18, a19, a20, a21, a22, a23, a24, a25, a26, a27, a28, a29))
End Select
End Function
End Function