From 7f944e1e25faa8d8c077ba78e4fd489b69270fb5 Mon Sep 17 00:00:00 2001
From: clifford <clifford@b57f626f-c46c-0410-a088-ec61d464b74c>
Date: Wed, 13 Jan 2010 12:24:24 +0000
Subject: [PATCH] Clifford Wolf: 	Added child() statement

git-svn-id: http://svn.clifford.at/openscad/trunk@275 b57f626f-c46c-0410-a088-ec61d464b74c
---
 TODO.txt                 |  2 --
 context.cc               |  1 +
 control.cc               | 22 ++++++++++++++++++++++
 examples/example018.scad | 23 +++++++++++++++++++++++
 module.cc                |  9 +++------
 openscad.h               |  1 +
 6 files changed, 50 insertions(+), 8 deletions(-)
 create mode 100644 examples/example018.scad

diff --git a/TODO.txt b/TODO.txt
index 8f4dbc46..64019cc9 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -49,12 +49,10 @@ o Advanced Transformations
   - Add statement for 2D and 3D minkowski sum
   - Add statement for refinement via surface subdivision
   - Add statement for intersections in cartesian product of childs
-  - Add statement for mirroring objects (without inverting them)
 o Function-Module-Interface
   - Pass a module instanciation to a function (e.g. for a volume() function)
   - Pass a function to a module instanciation (e.g. for dynamic extrusion paths)
 o Language Frontend
-  - Allow using the childs of a module instance inside the module
   - Allow local variables and functions everywhere (not only on module level)
 o DXF Import
   - Support for POLYLINE entity
diff --git a/context.cc b/context.cc
index 59c263a1..15a2ea6d 100644
--- a/context.cc
+++ b/context.cc
@@ -26,6 +26,7 @@ Context::Context(const Context *parent)
 	this->parent = parent;
 	functions_p = NULL;
 	modules_p = NULL;
+	inst_p = NULL;
 	ctx_stack.append(this);
 }
 
diff --git a/control.cc b/control.cc
index c898dfc9..19c52557 100644
--- a/control.cc
+++ b/control.cc
@@ -24,6 +24,7 @@
 #include "printutils.h"
 
 enum control_type_e {
+	CHILD,
 	ECHO,
 	ASSIGN,
 	FOR,
@@ -81,6 +82,26 @@ void for_eval(AbstractNode *node, int l, const QVector<QString> &call_argnames,
 
 AbstractNode *ControlModule::evaluate(const Context*, const ModuleInstantiation *inst) const
 {
+	if (type == CHILD)
+	{
+		int n = 0;
+		if (inst->argvalues.size() > 0) {
+			double v;
+			if (inst->argvalues[0].getnum(v))
+				n = v;
+		}
+		for (int i = Context::ctx_stack.size()-1; i >= 0; i--) {
+			const Context *c = Context::ctx_stack[i];
+			if (c->inst_p) {
+				if (n < c->inst_p->children.size())
+					return c->inst_p->children[n]->evaluate(c->inst_p->ctx);
+				return NULL;
+			}
+			c = c->parent;
+		}
+		return NULL;
+	}
+
 	AbstractNode *node;
 
 	if (type == INT_FOR)
@@ -135,6 +156,7 @@ AbstractNode *ControlModule::evaluate(const Context*, const ModuleInstantiation
 
 void register_builtin_control()
 {
+	builtin_modules["child"] = new ControlModule(CHILD);
 	builtin_modules["echo"] = new ControlModule(ECHO);
 	builtin_modules["assign"] = new ControlModule(ASSIGN);
 	builtin_modules["for"] = new ControlModule(FOR);
diff --git a/examples/example018.scad b/examples/example018.scad
new file mode 100644
index 00000000..15ed745f
--- /dev/null
+++ b/examples/example018.scad
@@ -0,0 +1,23 @@
+
+module step(len, mod)
+{
+	for (i = [0:$children-1])
+		translate([ len*(i - ($children-1)/2), 0, 0 ]) child((i+mod) % $children);
+}
+
+for (i = [1:4])
+{
+	translate([0, -250+i*100, 0]) step(100, i)
+	{
+		sphere(30);
+		cube(60, true);
+		cylinder(r = 30, h = 50, center = true);
+	
+		union() {
+			cube(45, true);
+			rotate([45, 0, 0]) cube(50, true);
+			rotate([0, 45, 0]) cube(50, true);
+			rotate([0, 0, 45]) cube(50, true);
+		}
+	}
+}
diff --git a/module.cc b/module.cc
index e58cdd1d..a319e1ee 100644
--- a/module.cc
+++ b/module.cc
@@ -117,6 +117,9 @@ AbstractNode *Module::evaluate(const Context *ctx, const ModuleInstantiation *in
 	Context c(ctx);
 	c.args(argnames, argexpr, inst->argnames, inst->argvalues);
 
+	c.inst_p = inst;
+	c.set_variable("$children", Value(double(inst->children.size())));
+
 	c.functions_p = &functions;
 	c.modules_p = &modules;
 
@@ -131,12 +134,6 @@ AbstractNode *Module::evaluate(const Context *ctx, const ModuleInstantiation *in
 			node->children.append(n);
 	}
 
-	foreach(ModuleInstantiation *v, inst->children) {
-		AbstractNode *n = v->evaluate(inst->ctx);
-		if (n != NULL)
-			node->children.append(n);
-	}
-
 	return node;
 }
 
diff --git a/openscad.h b/openscad.h
index 6a207890..8ad164d5 100644
--- a/openscad.h
+++ b/openscad.h
@@ -396,6 +396,7 @@ public:
 	QHash<QString, Value> config_variables;
 	const QHash<QString, AbstractFunction*> *functions_p;
 	const QHash<QString, AbstractModule*> *modules_p;
+	const ModuleInstantiation *inst_p;
 
 	static QVector<const Context*> ctx_stack;