Functions literals / higher order functions
I get
Compiling design (CSG Tree generation)...
ECHO: g3_x = function(x) g((x + a))
ERROR: Recursion detected calling function 'g' in file fn literals parkinbot.scad, line 4
TRACE: called by 'g', in file fn literals parkinbot.scad, line 4.
TRACE: called by 'g3', in file fn literals parkinbot.scad, line 13.
TRACE: called by 'echo', in file fn literals parkinbot.scad, line 13.
Compiling design (CSG Products generation)...
When I changed it to:
function move(a, g) =
function(x)
//echo(a,g)
g(x+a) ;
g1 = function(x) x;
g2 = move(0,g1);
g3 = move(1,g2);
echo(g3_x=g3);
echo(g3_2=g3(2));
removing the comments causes a seeming infinite recursion echoing to the console, had to quit the
gui, then it crashed.
From: Discuss [mailto:discuss-bounces@lists.openscad.org] On Behalf Of Ronaldo Persiano
Sent: Tue, 26 Nov 2019 11:08
To: OpenSCAD general discussion
Subject: Re: [OpenSCAD] Functions literals / higher order functions
I can't see why the following generates a stack overflow:
function move(a, g) =
function(x) g(x+a) ;
g1 = function(x) x;
g2 = move(0,g1);
g3 = move(0,g2);
echo(g3_x=g3);
echo(g3_2=g3(2));
If g3 is defined as g2 no error is reported.
I expect it is a scope issue with the 'move' function, I'll mention it on GitHub.
From: Discuss [mailto:discuss-bounces@lists.openscad.org] On Behalf Of Michael Marx
Sent: Tue, 26 Nov 2019 11:51
To: 'OpenSCAD general discussion'
Subject: Re: [OpenSCAD] Functions literals / higher order functions
I get
Compiling design (CSG Tree generation)...
ECHO: g3_x = function(x) g((x + a))
ERROR: Recursion detected calling function 'g' in file fn literals parkinbot.scad, line 4
TRACE: called by 'g', in file fn literals parkinbot.scad, line 4.
TRACE: called by 'g3', in file fn literals parkinbot.scad, line 13.
TRACE: called by 'echo', in file fn literals parkinbot.scad, line 13.
Compiling design (CSG Products generation)...
When I changed it to:
function move(a, g) =
function(x)
//echo(a,g)
g(x+a) ;
g1 = function(x) x;
g2 = move(0,g1);
g3 = move(1,g2);
echo(g3_x=g3);
echo(g3_2=g3(2));
removing the comments causes a seeming infinite recursion echoing to the console, had to quit the
gui, then it crashed.
From: Discuss [mailto:discuss-bounces@lists.openscad.org] On Behalf Of Ronaldo Persiano
Sent: Tue, 26 Nov 2019 11:08
To: OpenSCAD general discussion
Subject: Re: [OpenSCAD] Functions literals / higher order functions
I can't see why the following generates a stack overflow:
function move(a, g) =
function(x) g(x+a) ;
g1 = function(x) x;
g2 = move(0,g1);
g3 = move(0,g2);
echo(g3_x=g3);
echo(g3_2=g3(2));
If g3 is defined as g2 no error is reported.
As I mentioned On GitHub here
https://github.com/openscad/openscad/pull/3077#issuecomment-558417555 ,
this stops the infinite recursion, don't know why, need caffeine...
function move(a, g) = echo(move=a,g)
function(x)
echo(g_in_move=a,x)
(x+a) ;
g1 = function(x)
x;
g2 = move(1,g1);
g3 = move(3,g2);
echo(g1_=g1);
echo(g1_1=g1(1));
echo(g2_=g2);
echo(g2_7=g2(7));
echo(g3_x=g3);
echo(g3_5=g3(5));
Gets:
Compiling design (CSG Tree generation)...
ECHO: move = 1, function(x) x
ECHO: move = 3, function(x) echo(g_in_move = a, x) (x + a)
ECHO: g1_ = function(x) x
ECHO: g1_1 = 1
ECHO: g2_ = function(x) echo(g_in_move = a, x) (x + a)
ECHO: g_in_moveg = 1, 7
ECHO: g2_7 = 8
ECHO: g3_x = function(x) echo(g_in_move = a, x) (x + a)
ECHO: g_in_moveg = 3, 5
ECHO: g3_5 = 8
Compiling design (CSG Products generation)...
Geometries in cache: 0
Admin - email* me if you need anything, or if I've done something stupid...
- click on my MichaelAtOz label, there is a link to email me.
Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above.
--
Sent from: http://forum.openscad.org/
Michael,
You may need another coffee after confirming that the following runs
without error:
function move(a, g) =
function(x) g(x+a) ;
g1 = function(x) x;
g2 = move(0,g1);
//g0 = g2;
g0 = function(x) g2(x) ;
g3 = move(0,g0);
echo(g3_x=g3);
echo(g3_2=g3(2));
unless the commented line substitute the g0 definition.
Compiling design (CSG Tree generation)...
ECHO: g3_x = function(x) g((x + a))
ECHO: g3_2 = 2
Compiling design (CSG Products generation)...
Geometries in cache: 5
Geometry cache size in bytes: 1774120
CGAL Polyhedrons in cache: 0
CGAL cache size in bytes: 0
Compiling design (CSG Products normalization)...
Normalized CSG tree has 0 elements
Compile and preview finished.
Total rendering time: 0 hours, 0 minutes, 0 seconds
Inserting an indirection also works fine:
function move(a, g) =
function(x) identity(x+a) ;
function identity(x) = x;
g1 = function(x) x;
g2 = move(0,g1);
g3 = move(0,g2);
echo(g3_x=g3);
echo(g3_2=g3(2));
Oops, at line 4, dropped the g() in my edits...
Admin - email* me if you need anything, or if I've done something stupid...
- click on my MichaelAtOz label, there is a link to email me.
Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above.
--
Sent from: http://forum.openscad.org/
I followed Michael and also dropped the g. But anyway, the last code still
works fine with
function move(a, g) =
function(x) identity(g(x+a)) ;
Em ter., 26 de nov. de 2019 às 02:23, Ronaldo Persiano <
rcmpersiano@gmail.com> escreveu:
Inserting an indirection also works fine:
function move(a, g) =
function(x) identity(x+a) ;
function identity(x) = x;
g1 = function(x) x;
g2 = move(0,g1);
g3 = move(0,g2);
echo(g3_x=g3);
echo(g3_2=g3(2));
See https://github.com/openscad/openscad/pull/3077#issuecomment-558442998
assert() helps, feels like a scope problem, but I need paper and pencil, my
head is filling with virtual functions...I don't like function literals...
Admin - email* me if you need anything, or if I've done something stupid...
- click on my MichaelAtOz label, there is a link to email me.
Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above.
--
Sent from: http://forum.openscad.org/
Yet another hack that works:
function move(a, g) =
function(x)
let( v = g(x+a) ) v;
g1 = function(x) x;
g2 = move(2, g1);
g3 = move(3, g2);
echo(g3_x=g3);
echo(g3_2=g3(2));
Compiling design (CSG Tree generation)...
ECHO: g3_x = function(x) let(v = g((x + a))) v
ECHO: g3_2 = 7
Compiling design (CSG Products generation)...
Geometries in cache: 1
Geometry cache size in bytes: 270008
CGAL Polyhedrons in cache: 0
CGAL cache size in bytes: 0
Compiling design (CSG Products normalization)...
Normalized CSG tree has 0 elements
Compile and preview finished.
I can't see how scope may matter here.
Not normal scope, a bug in how it works.
function move(a, g) = echo(move=a,g)
function(m)
echo(m_in_move=a,m,g)
assert(m<12)
g(echo(str("call g(",m+a,")[g=",g,"]")) m+a) ;
g1 = function(x)
echo(fx=x)
x;
g2 = move(2,g1);
g3 = move(3,g2);
echo(g2_=g2);
echo(g3_x=g3);
echo(g3_5=g3(5));
Produces
Compiling design (CSG Tree generation)...
ECHO: move = 2, function(x) echo(fx = x) x
ECHO: move = 3, function(m) echo(m_in_move = a, m, g) assert((m
ECHO: g2_ = function(m) echo(m_in_move = a, m, g) assert((m
ECHO: g3_x = function(m) echo(m_in_move = a, m, g) assert((m
ECHO: m_in_move = 3, 5, function(m) echo(m_in_move = a, m, g) assert((m
ECHO: "call g(8)[g=function(m) echo(m_in_move = a, m, g) assert((m
ECHO: "call g(8)[g=function(m) echo(m_in_move = a, m, g) assert((m
ECHO: m_in_move = 2, 8, function(x) echo(fx = x) x
ECHO: "call g(10)[g=function(x) echo(fx = x) x]"
ECHO: m_in_move = 2, 10, function(x) echo(fx = x) x
ECHO: "call g(12)[g=function(x) echo(fx = x) x]"
ECHO: m_in_move = 2, 12, function(x) echo(fx = x) x
ERROR: Assertion '(m < 12)' failed in file fn literals ronaldo.scad, line 4
TRACE: called by 'g', in file fn literals ronaldo.scad, line 5.
TRACE: called by 'g3', in file fn literals ronaldo.scad, line 15.
TRACE: called by 'echo', in file fn literals ronaldo.scad, line 15.
Compiling design (CSG Products generation)...
Geometries in cache: 0
You can see it is saying it wants to call g1, but is actually calling g2 recursively.
From: Discuss [mailto:discuss-bounces@lists.openscad.org] On Behalf Of Ronaldo Persiano
Sent: Tue, 26 Nov 2019 22:58
To: OpenSCAD general discussion
Subject: Re: [OpenSCAD] Functions literals / higher order functions
Yet another hack that works:
function move(a, g) =
function(x)
let( v = g(x+a) ) v;
g1 = function(x) x;
g2 = move(2, g1);
g3 = move(3, g2);
echo(g3_x=g3);
echo(g3_2=g3(2));
Compiling design (CSG Tree generation)...
ECHO: g3_x = function(x) let(v = g((x + a))) v
ECHO: g3_2 = 7
Compiling design (CSG Products generation)...
Geometries in cache: 1
Geometry cache size in bytes: 270008
CGAL Polyhedrons in cache: 0
CGAL cache size in bytes: 0
Compiling design (CSG Products normalization)...
Normalized CSG tree has 0 elements
Compile and preview finished.
I can't see how scope may matter here.