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Using the new Python--OpenSCAD to write out files (and to have Python functions and OpenSCAD variables in a loaded module)

William F. Adams

Sat, Sep 23, 2023 4:30 AM

Maybe this is all obvious to folks, but it took me a while to wrap my mind around how this works:

There are two ways to incorporate files into OpenSCAD:

use — this will allow definitions in either Python, or in OpenSCAD and using a mix of OpenSCAD and Python code
include — this allows using variables from the main OpenSCAD file, but does not allow directly making use a function defined in Python

Since we want to be able to turn on/off calling Python from w/in OpenSCAD we require a total of 3 files:

a Python file which is loaded using use <gcodepreview.py>; — this is able to define Python functions
an OpenSCAD file which is loaded using use <pygcodepreview.scad>; — this wraps the defined Python function in OpenSCAD
an OpenSCAD file which is loaded using include <gcodepreview.scad>; — this allows using OpenSCAD variables from the main file to determine whether or no an OpenSCAD module which calls a Python module should be called

Thus we have:

gcodepreview.py
def popengcodefile(fn):
global f
f = open(fn, "w")

def writeln(*arguments):
line_to_write = ""
for element in arguments:
line_to_write += element
f.write(line_to_write)
f.write("\n")

def pclosegcodefile():
f.close()

pygcodepreview.scad
//!OpenSCAD

module oopengcodefile(fn) {
popengcodefile(fn);
}

module owritecomment(comment) {
writeln("(",comment,")");
}

module oclosegcodefile() {
pclosegcodefile();
}

gcodepreview.scad
//!OpenSCAD

module opengcodefile(fn) {
if (generategcode == true) {
oopengcodefile(fn);
}
}

module writecomment(comment) {
if (generategcode == true) {
owritecomment(comment);
}
}

module closegcodefile() {
if (generategcode == true) {
oclosegcodefile();
}
}

which is all put together by an OpenSCAD file:
//!OpenSCAD

use <gcodepreview.py>;
use <pygcodepreview.scad>;
include <gcodepreview.scad>;

/* [G-code] /
Gcode_filename = "gcode.nc";
/ [G-code] */
generategcode = true;

a = 300;

opengcodefile(Gcode_filename);

writecomment(str(a));

writecomment("Test");

closegcodefile();

which when run, creates the file:

gcode.nc
(300)
(Test)
Which finally allows me to write out files from OpenSCAD in a workable fashion.
My thanks to everyone for their patience and generosity in helping me to this point.
William

Maybe this is all obvious to folks, but it took me a while to wrap my mind around how this works: There are two ways to incorporate files into OpenSCAD: - use — this will allow definitions in either Python, or in OpenSCAD and using a mix of OpenSCAD and Python code - include — this allows using variables from the main OpenSCAD file, but does not allow directly making use a function defined in Python Since we want to be able to turn on/off calling Python from w/in OpenSCAD we require a total of 3 files: - a Python file which is loaded using use <gcodepreview.py>; — this is able to define Python functions - an OpenSCAD file which is loaded using use <pygcodepreview.scad>; — this wraps the defined Python function in OpenSCAD - an OpenSCAD file which is loaded using include <gcodepreview.scad>; — this allows using OpenSCAD variables from the main file to determine whether or no an OpenSCAD module which calls a Python module should be called Thus we have: gcodepreview.py def popengcodefile(fn): global f f = open(fn, "w") def writeln(*arguments): line_to_write = "" for element in arguments: line_to_write += element f.write(line_to_write) f.write("\n") def pclosegcodefile(): f.close() pygcodepreview.scad //!OpenSCAD module oopengcodefile(fn) { popengcodefile(fn); } module owritecomment(comment) { writeln("(",comment,")"); } module oclosegcodefile() { pclosegcodefile(); } gcodepreview.scad //!OpenSCAD module opengcodefile(fn) { if (generategcode == true) { oopengcodefile(fn); } } module writecomment(comment) { if (generategcode == true) { owritecomment(comment); } } module closegcodefile() { if (generategcode == true) { oclosegcodefile(); } } which is all put together by an OpenSCAD file: //!OpenSCAD use <gcodepreview.py>; use <pygcodepreview.scad>; include <gcodepreview.scad>; /* [G-code] */ Gcode_filename = "gcode.nc"; /* [G-code] */ generategcode = true; a = 300; opengcodefile(Gcode_filename); writecomment(str(a)); writecomment("Test"); closegcodefile(); which when run, creates the file: gcode.nc (300) (Test) Which finally allows me to write out files from OpenSCAD in a workable fashion. My thanks to everyone for their patience and generosity in helping me to this point. William