Parameter modifier of ":" -- documented?
20 Dec 2017 03:11 - 20 Dec 2017 03:12 #103375
by GaryLa
Parameter modifier of ":" -- documented? was created by GaryLa
The files move.ngc and line.ngc have a parameter format I've not seen before. Chapter 3 of the documentation doesn't mention this format either.
Is it a "member" modifier allowing a variable to have members like structures have? If so, what declarations (if any) are necessary?
Or, is it just to reference a local var from another function? If so, then why does move reference its own locals this way?
BTW, the format is #<variable:mystery> and used as:
#<variable:mystery> = value
Is it a "member" modifier allowing a variable to have members like structures have? If so, what declarations (if any) are necessary?
Or, is it just to reference a local var from another function? If so, then why does move reference its own locals this way?
BTW, the format is #<variable:mystery> and used as:
#<variable:mystery> = value
Last edit: 20 Dec 2017 03:12 by GaryLa.
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20 Dec 2017 03:40 #103377
by dgarrett
Replied by dgarrett on topic Parameter modifier of ":" -- documented?
The use of global names like #<_line:len>,
#<_move:phi> is just a convention used for
communication of results in some of the provided
ngcgui examples and for handling of entry boxes.
From the docs:
Ref: linuxcnc.org/docs/2.7/html/gui/ngcgui.html
The source file text gives some more background:
Ref: github.com/LinuxCNC/linuxcnc/blob/2.7/tcl/ngcgui.tcl#L89
#<_move:phi> is just a convention used for
communication of results in some of the provided
ngcgui examples and for handling of entry boxes.
From the docs:
While input global named parameters are
discouraged, linuxCNC subroutines must use global
named parameters for returning results. Since
ngcgui-compatible subfiles are aimed at gui usage,
return values are not a common requirement.
However, ngcgui is useful as a testing tool for
subroutines which do return global named
parameters and it is common for ngcgui-compatible
subfiles to call utility subroutine files that
return results with global named parameters.
To support these usages, ngcgui ignores global
named parameters that include a colon (:)
character in their name. Use of the colon (:) in
the name prevents ngcgui from making entryboxes
for these parameters.Ref: linuxcnc.org/docs/2.7/html/gui/ngcgui.html
The source file text gives some more background:
# The linuxcnc gcode language does not provide a
# mechanism for returning results so subroutines
# must set global parameters for results. Within
# ngcgui, _globals with names that contain a colon
# (:) character are ignored in the creation of
# entry boxes. For example, a subroutine called
# from a Subfile named o<line> returns results in
# globals like: #<_line:theta>, $<_line:length>,
# etc. This feature can be used to hide globals
# from entry boxes for any purpose or for
# communication between routinesRef: github.com/LinuxCNC/linuxcnc/blob/2.7/tcl/ngcgui.tcl#L89
The following user(s) said Thank You: GaryLa
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