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Implemented NextAre #1001

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Merged
pharring merged 4 commits into from
Mar 6, 2015
Merged

Implemented NextAre #1001

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78e3009
Implemented NextAre
AdamSpeight2008 Mar 4, 2015
6396a55
Inserted an empty line after NextAre method.
AdamSpeight2008 Mar 4, 2015
ae2f283
NextAre implementation change.
AdamSpeight2008 Mar 5, 2015
6326f2d
Clearing Up additional blank line.
AdamSpeight2008 Mar 5, 2015
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59 changes: 23 additions & 36 deletions src/Compilers/VisualBasic/Portable/Scanner/Scanner.vb
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Original file line number Diff line number Diff line change
Expand Up @@ -389,6 +389,17 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Syntax.InternalSyntax
#End Region

#Region "Buffer helpers"

@VladimirReshetnikov VladimirReshetnikov Mar 4, 2015

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Have you measured performance effects of this change? Is this method being inlined by JIT?

@AdamSpeight2008 AdamSpeight2008 Mar 4, 2015

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The build I have is Debug so it isn't optimised. It the IL it is a method call.

    IL_00ce: nop
    IL_00cf: ldarg.0
    IL_00d0: ldloc.1
    IL_00d1: ldc.i4.2
    IL_00d2: add
    IL_00d3: ldstr "CDATA["
    IL_00d8: call instance bool Microsoft.CodeAnalysis.VisualBasic.Syntax.InternalSyntax.Scanner::NextAre(int32, string)
    IL_00dd: ldc.i4.0
    IL_00de: ceq
    IL_00e0: stloc.2
    IL_00e1: ldloc.2
    IL_00e2: brtrue.s IL_00f2

Since its been extracted out we can "play" with different internal implementations.

Private Function NextAre(offset As Integer, chars As String) As Boolean
Debug.Assert(Not String.IsNullOrEmpty(chars))
Dim n = chars.Length
If Not CanGetCharAtOffset(offset + n) Then Return False
For i = 0 To n - 1
If chars(i) <> PeekAheadChar(offset + i) Then Return False
Next
Return True
End Function

@VladimirReshetnikov VladimirReshetnikov Mar 4, 2015

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Please separate method declarations with an empty line.

@AdamSpeight2008 AdamSpeight2008 Mar 4, 2015

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So noted and added in 6396a55

@gafter gafter Mar 4, 2015

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Can you please rewrite this method for clarity as suggested by @pharring In the issue thread?


Private Function CanGetChar() As Boolean
Return _lineBufferOffset < _bufferLen
End Function
Expand Down Expand Up @@ -1109,9 +1120,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Syntax.InternalSyntax
Return ScanStringLiteral(precedingTrivia)

Case "A"c
If CanGetCharAtOffset(2) AndAlso
PeekAheadChar(1) = "s"c AndAlso
PeekAheadChar(2) = " "c Then
If NextAre(1, "s ") Then

' TODO: do we allow widechars in keywords?
Dim spelling = "As"
Expand All @@ -1122,10 +1131,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Syntax.InternalSyntax
End If

Case "E"c
If CanGetCharAtOffset(3) AndAlso
PeekAheadChar(1) = "n"c AndAlso
PeekAheadChar(2) = "d"c AndAlso
PeekAheadChar(3) = " "c Then
If NextAre(1, "nd ") Then

' TODO: do we allow widechars in keywords?
Dim spelling = "End"
Expand All @@ -1136,9 +1142,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Syntax.InternalSyntax
End If

Case "I"c
If CanGetCharAtOffset(2) AndAlso
PeekAheadChar(1) = "f"c AndAlso
PeekAheadChar(2) = " "c Then
If NextAre(1, "f ") Then

' TODO: do we allow widechars in keywords?
Dim spelling = "If"
Expand All @@ -1148,9 +1152,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Syntax.InternalSyntax
Return ScanIdentifierOrKeyword(precedingTrivia)
End If

Case "a"c, "b"c, "c"c, "d"c, "e"c, "f"c, "g"c, "h"c, "i"c, "j"c, "k"c, "l"c,
"m"c, "n"c, "o"c, "p"c, "q"c, "r"c, "s"c, "t"c, "u"c, "v"c, "w"c, "x"c,
"y"c, "z"c
Case "a"c, "b"c, "c"c, "d"c, "e"c, "f"c, "g"c, "h"c, "i"c, "j"c, "k"c, "l"c, "m"c,
"n"c, "o"c, "p"c, "q"c, "r"c, "s"c, "t"c, "u"c, "v"c, "w"c, "x"c, "y"c, "z"c
Return ScanIdentifierOrKeyword(precedingTrivia)

Case "B"c, "C"c, "D"c, "F"c, "G"c, "H"c, "J"c, "K"c, "L"c, "M"c, "N"c, "O"c, "P"c, "Q"c,
Expand Down Expand Up @@ -1347,43 +1350,32 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Syntax.InternalSyntax
Return ScanStringLiteral(precedingTrivia)

Case "A"c
If CanGetCharAtOffset(2) AndAlso
PeekAheadChar(1) = "s"c AndAlso
PeekAheadChar(2) = " "c Then

If NextAre(1, "s ") Then
Dim spelling = GetText(2)
Return MakeKeyword(SyntaxKind.AsKeyword, spelling, precedingTrivia)
Else
Return ScanIdentifierOrKeyword(precedingTrivia)
End If

Case "E"c
If CanGetCharAtOffset(3) AndAlso
PeekAheadChar(1) = "n"c AndAlso
PeekAheadChar(2) = "d"c AndAlso
PeekAheadChar(3) = " "c Then

If NextAre(1, "nd ") Then
Dim spelling = GetText(3)
Return MakeKeyword(SyntaxKind.EndKeyword, spelling, precedingTrivia)
Else
Return ScanIdentifierOrKeyword(precedingTrivia)
End If

Case "I"c
If CanGetCharAtOffset(2) AndAlso
PeekAheadChar(1) = "f"c AndAlso
PeekAheadChar(2) = " "c Then

If NextAre(1, "f ") Then
' TODO: do we allow widechars in keywords?
Dim spelling = GetText(2)
Return MakeKeyword(SyntaxKind.IfKeyword, spelling, precedingTrivia)
Else
Return ScanIdentifierOrKeyword(precedingTrivia)
End If

Case "a"c, "b"c, "c"c, "d"c, "e"c, "f"c, "g"c, "h"c, "i"c, "j"c, "k"c, "l"c,
"m"c, "n"c, "o"c, "p"c, "q"c, "r"c, "s"c, "t"c, "u"c, "v"c, "w"c, "x"c,
"y"c, "z"c
Case "a"c, "b"c, "c"c, "d"c, "e"c, "f"c, "g"c, "h"c, "i"c, "j"c, "k"c, "l"c, "m"c,
"n"c, "o"c, "p"c, "q"c, "r"c, "s"c, "t"c, "u"c, "v"c, "w"c, "x"c, "y"c, "z"c
Return ScanIdentifierOrKeyword(precedingTrivia)

Case "B"c, "C"c, "D"c, "F"c, "G"c, "H"c, "J"c, "K"c, "L"c, "M"c, "N"c, "O"c, "P"c, "Q"c,
Expand Down Expand Up @@ -1496,13 +1488,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Syntax.InternalSyntax
Return XmlMakeBeginCommentToken(precedingTrivia, scanTrailingTrivia)
End If
Case "["c
If CanGetCharAtOffset(length + 8) AndAlso
PeekAheadChar(length + 2) = "C"c AndAlso
PeekAheadChar(length + 3) = "D"c AndAlso
PeekAheadChar(length + 4) = "A"c AndAlso
PeekAheadChar(length + 5) = "T"c AndAlso
PeekAheadChar(length + 6) = "A"c AndAlso
PeekAheadChar(length + 7) = "["c Then

If NextAre(length + 2, "CDATA[") Then

Return XmlMakeBeginCDataToken(precedingTrivia, scanTrailingTrivia)
End If
Expand Down