Empty argument prevents further arguments passed to function

[edanaher]

Upfront Information

Please provide the following information by running the command and providing
the output.

• Fvwm3 version (run: fvwm3 --version)

fvwm3 1.0.9 (released)                                                          
with support for:  ReadLine, XPM, PNG, SVG, Shape, XShm, SM, Bidi text, XRandR, 
XRender, XCursor, XFT, NLS                           

• Linux distribution or BSD name/version

NixOS unstable

• Platform (run: uname -sp)

Linux unknown

Expected Behaviour

When parsing arguments, and empty string should be passed in as an argument. E.g., the following should product a binding for raising a window on alt-click, and moving if the mouse is then dragged:

AddToFunc MapMouse
+ I AddToFunc EvanMouse$0$1$2
+ I + I $3
+ I + C $4
+ I + D $5
+ I + M $6
+ I + H $7
+ I Mouse $0 $1 $2 EvanMouse$0$1$2

MapMouse 1 W M Raise '' Lower       Move   Move

Or the following should echo A..B.C on startup:

AddToFunc EchoArgs
+ I Exec echo $0.$1.$2.$3
EchoArgs A '' B C

Indeed, this is the behavior in fvwm2.

Actual Behaviour

In the first case, only the first binding occurs; in the second, the output is A...

It looks like when an empty argument is provided, the remaining arguments are ignored. In my case, I can work around this by replacing the empty string with a single space, which seems to have the same behavior. But the readme still says "An existing version 2 configuration currently works"; this violates that statement.

Steps to Reproduce

The config files provided above are pretty minimal, and as noted, fvwm2 behaves as expected.

[somiaj]

@edanaher Although not a fix for this issue in general, fvwm's Nop command is essentially a place keeper for do nothing. The example you gave there should work with MapMouse 1 W M Raise Nop Lower Move Move. Also in your case + C without any options could also cause problems, while + C Nop would just do nothing.