VBA - Find all numbered lines in VBE Modules via pattern search

Question

Task:

My goal is to find all numbered lines in procedures of my Code Modules. The CodeModule.Find method can be used to check for search terms (target parameter).

Syntax:

object.Find(target, startline, startcol, endline, endcol [, wholeword] [, matchcase] [, patternsearch])

The referring help site https://msdn.microsoft.com/en-us/library/aa443952(v=vs.60).aspx states: parameter patternsearch: Optional. A Boolean value specifying whether or not the target string is a regular expression pattern. If True, the target string is a regular expression pattern. False is the default.

As explained above the find method allows a regex pattern search, which I would like to use in order to identify numbered lines in a precise way: digits followed by a tab. The example below therefore defines a search string s and sets the last parameter PatternSearch in the .Find method to True.

Problem AFAIK a valid regex definition could be

s = "[0-9]{1,4}[ \t]"

but that doesn't show anything, not even an error.

In order to show at least any results, I defined the search term

s = "[0-9]*[ \t]*)"

in the calling example procedure ListNumberedLines showing erratic results.

Question

Is there any possibility to use a valid regex patternsearch in the CodeModule.Find method?

Example code

Option Explicit

' ==============
' Example Search
' ==============
Sub ListNumberedLines()
'  Declare search pattern string s
   Dim S As String
10  S = "[0-9]*[ \t]*)"     
20  Debug.Print "Search Term: " & S
30  Call findWordInModules(S)

End Sub

Public Sub findWordInModules(ByVal sSearchTerm As String)
' Purpose: find modules ('components') with lines containing a search term
' Method:  .CodeModule.Find with last parameter patternsearch set to True
' Based on https://www.devhut.net/2016/02/24/vba-find-term-in-vba-modulescode/

' VBComponent requires reference to Microsoft Visual Basic for Applications Extensibility
'             or keep it as is and use Late Binding instead
' Declare module variable oComponent
  Dim oComponent            As Object    'VBComponent

  For Each oComponent In Application.VBE.ActiveVBProject.VBComponents
    If oComponent.CodeModule.Find(sSearchTerm, 1, 1, -1, -1, False, False, True) = True Then
        Debug.Print "Module: " & oComponent.Name  'Name of the current module in which the term was found (at least once)
        'Need to execute a recursive listing of where it is found in the module since it could be found more than once
        Call listLinesinModuleWhereFound(oComponent, sSearchTerm)
    End If
  Next oComponent
End Sub

Sub listLinesinModuleWhereFound(ByVal oComponent As Object, ByVal sSearchTerm As String)
' Purpose: list module lines containing a search term
' Method:  .CodeModule.Find with last parameter patternsearch set to True
  Dim lTotalNoLines         As Long   'total number of lines within the module being examined
  Dim lLineNo               As Long   'will return the line no where the term is found
    lLineNo = 1
  With oComponent         ' Module
    lTotalNoLines = .CodeModule.CountOfLines
    Do While .CodeModule.Find(sSearchTerm, lLineNo, 1, -1, -1, False, False, True) = True
        Debug.Print vbTab & "Zl. " & lLineNo & "|" & _
                    Trim(.CodeModule.Lines(lLineNo, 1))  'Remove any padding spaces
        lLineNo = lLineNo + 1    'Restart the search at the next line looking for the next occurence
    Loop
  End With
End Sub

Answer 1

As @MatsMug says, parsing VBA with Regex is hard impossible, but line-numbers are a simpler case, and should be findable with regex alone.

Fortunately, line numbers can only appear within a procedure body (including before the End Sub/Function/Property statement), so we know they'll never be the first line of your code.

Unfortunately, you can prefix a line-label with 0 or more line continuations:

Sub Foo()
 _
 _
10 Beep
End Sub

Furthermore, a line number isn't always followed by a space - it can be followed by an instruction separator, giving the line-number the appearance of a line-label:

Sub foo()
10: Beep
End Sub

And if you're code is evil, you might encounter a negative line-number (entered by using hex notation - which VBE dutifully pretty prints back to the code-pane with a leading space and a negative number):

Sub foo()
10 Beep
 -1 Beep
End Sub

And we also need to be able to identify numbers that appear on a continued line, that aren't line-numbers:

Sub foo()
  Debug.Print _
5 & "is not a line-number"
End Sub

So, here's some evil line-numbering, with a mix of all of those edge-cases:

Option Explicit

Sub foo()

5: Beep

 _
 _
 _
10 Beep

20 _
'Debug.Print _
30

50: Beep

40 Beep

 _
 -1 _
 Beep 'The "-1" line number is achieved by entering "&HFFFFFFFF"

Debug.Print _
2 & "is not a line-number"

60 End Sub

And here's some regex that identifies the line-numbers:

(?<! _)\n( _\n)* ?(?<line_number>(?:\-)?\d+)[: ]

And here's a syntax highlight from regex101:

Answer 2

For the longest time, Rubberduck was struggling with properly/formally parsing line numbers - our work-around was to remove them (replacing them with spaces) before feeding the code module contents to our parser.

Recently we've managed to formally define line numbers:

// lineNumberLabel should actually be "statement-label" according to MS VBAL but they only allow lineNumberLabels:
// A <statement-label> that occurs as the first element of a <list-or-label> element has the effect 
// as if the <statement-label> was replaced with a <goto-statement> containing the same 
// <statement-label>. This <goto-statement> takes the place of <line-number-label> in 
// <statement-list>.  
listOrLabel :
    lineNumberLabel (whiteSpace? COLON whiteSpace? sameLineStatement?)*
    | (COLON whiteSpace?)? sameLineStatement (whiteSpace? COLON whiteSpace? sameLineStatement?)*
;
sameLineStatement : blockStmt;

And lineNumberLabel is defined as:

//Statement labels can only appear at the start of a line.
statementLabelDefinition : {_input.La(-1) == NEWLINE}? (combinedLabels | identifierStatementLabel | standaloneLineNumberLabel);
identifierStatementLabel : unrestrictedIdentifier whiteSpace? COLON; 

standaloneLineNumberLabel : 
    lineNumberLabel whiteSpace? COLON
    | lineNumberLabel;
combinedLabels : lineNumberLabel whiteSpace identifierStatementLabel;
lineNumberLabel : numberLiteral;

(full Antlr4 grammar here)

Notice the predicate {_input.La(-1) == NEWLINE}?, which force the parser rule to only match a statementLabelDefinition at the start of a line - a logical line of code.

You see VBA code has physical code lines, like what you're getting from the CodeModule's contents. But VBA code also has a concept of logical code lines, and it turns out that is all the parser cares about.

This would trip any typical regex:

Sub DoSomething()
    Debug.Print _
42
End Sub

There's only 1 logical line of code between the signature and the End Sub token, but a simple Find will happily consider that 42 as a "line number" ...which it isn't - it's the argument passed to Debug.Print, in the same instruction, on the same logical code line, but on the next physical code line.

And you can't be dealing with logical code lines without first pre-processing your input, to take line continuation tokens into account.

And in order to do that, you need to actually parse the instructions you're seeing - at least know where they start and where they end... and that's no small undertaking! see ThunderFrame's answer

The VBIDE API is extremely limited, and won't be helpful for that.

---

TL;DR: You can't parse VBA code with regular expressions alone. So, nope. Sorry! you need a much more complex regex pattern than that - see ThunderFrame's answer.