[RESOLVED] Regular expression question

[wbport]

In something to read clipboard data from a music notation program, I am not interested in a note if it has the Grace attribute, stem direction is missing, or spacing has already been applied. The following would fail

|Note|Dur:8th,Grace,Slur|Pos:#-1|Opts:Stem=Down,XAccSpace=1,XNoteSpace=1

for three reasons, but is the basis for a regular expression:

    result = lineU[iU].match(/\|Note\|Dur:.*(Grace)?.*Pos:([x#nbv]?)(-?\d*).*Stem=(Up|Down).*(Space=)?/)      // Look for |Note| with Stem=Up specfied, not Grace, no Space=
    if ((result != null) && (result[1] == "") && (result[5] == "")) {

Something that SHOULD pass is

|Note|Dur:4th|Pos:-2|Opts:Stem=Down

When I ran this in debugging mode, nothing was displayed for result[1] or [5] although result[2] was "" (No accidental). My question is how can I check for empty results in these two positions? TIA

[wbport]

Never mind. I am now checking for null rather than an empty string.

[007Julien]

Use test with something like this

var lnU=lineU[iU]
if ((!/Grace/.test(lnU)) && /Stem=(Up|Down)/.test(lnU) && (!/XNoteSpace=1/.test(lnU))) {
   // I am interested
}

[wbport]

I hadn't thought of doing a test in that order, but I'll have to keep that in mind for the future, thanks for looking at it. It worked when I checked for null so I uploaded it to spacepart.htm. Some test data:

!NoteWorthyComposerClip(2.5,Single)
|Clef|Type:Treble
|Note|Dur:4th|Pos:-1|Opts:Stem=Up
|Note|Dur:4th|Pos:-1|Opts:Stem=Up
|Note|Dur:4th|Pos:#-1|Opts:Stem=Up
|Note|Dur:4th|Pos:#-1|Opts:Stem=Up
!NoteWorthyComposerClip-End
********** above for top window, rest for bottom ******
!NoteWorthyComposerClip(2.5,Single)
|Clef|Type:Treble
|Note|Dur:4th|Pos:-2|Opts:Stem=Down
|Note|Dur:4th|Pos:#-2|Opts:Stem=Down
|Note|Dur:4th|Pos:-2|Opts:Stem=Down
|Note|Dur:4th|Pos:#-2|Opts:Stem=Down
!NoteWorthyComposerClip-End