Cleaned up argument list handling, related to #116

25 files changed, 131 insertions, 149 deletions

diff --git a/openscad.pro b/openscad.pro
index 00df471..0f3394e 100644
--- a/openscad.pro
+++ b/openscad.pro
@@ -187,7 +187,8 @@ FORMS   += src/MainWindow.ui \
            src/AboutDialog.ui \
            src/ProgressWidget.ui
 
-HEADERS += src/version_check.h \
+HEADERS += src/typedefs.h \
+           src/version_check.h \
            src/ProgressWidget.h \
            src/parsersettings.h \
            src/renderer.h \
diff --git a/src/cgaladv.cc b/src/cgaladv.cc
index 8c98ae6..aad3a95 100644
--- a/src/cgaladv.cc
+++ b/src/cgaladv.cc
@@ -46,23 +46,22 @@ AbstractNode *CgaladvModule::evaluate(const Context *ctx, const ModuleInstantiat
 {
 	CgaladvNode *node = new CgaladvNode(inst, type);
 
-	std::vector<std::string> argnames;
-	std::vector<Expression*> argexpr;
+	AssignmentList args;
 
 	if (type == MINKOWSKI)
-		argnames += "convexity";
+		args += Assignment("convexity", NULL);
 
 	if (type == GLIDE)
-		argnames += "path", "convexity";
+		args += Assignment("path", NULL), Assignment("convexity", NULL);
 
 	if (type == SUBDIV)
-		argnames += "type", "level", "convexity";
+		args += Assignment("type", NULL), Assignment("level", NULL), Assignment("convexity", NULL);
 
 	if (type == RESIZE)
-		argnames += "newsize", "auto";
+		args += Assignment("newsize", NULL), Assignment("auto", NULL);
 
 	Context c(ctx);
-	c.setVariables(argnames, argexpr, evalctx);
+	c.setVariables(args, evalctx);
 
 	Value convexity, path, subdiv_type, level;
 
diff --git a/src/color.cc b/src/color.cc
index 4e9c55d..6c3aaef 100644
--- a/src/color.cc
+++ b/src/color.cc
@@ -54,13 +54,12 @@ AbstractNode *ColorModule::evaluate(const Context *ctx, const ModuleInstantiatio
 	node->color[0] = node->color[1] = node->color[2] = -1.0;
 	node->color[3] = 1.0;
 
-	std::vector<std::string> argnames;
-	std::vector<Expression*> argexpr;
+	AssignmentList args;
 
-	argnames += "c", "alpha";
+	args += Assignment("c", NULL), Assignment("alpha", NULL);
 
 	Context c(ctx);
-	c.setVariables(argnames, argexpr, evalctx);
+	c.setVariables(args, evalctx);
 
 	Value v = c.lookup_variable("c");
 	if (v.type() == Value::VECTOR) {
diff --git a/src/context.cc b/src/context.cc
index 6189205..706407c 100644
--- a/src/context.cc
+++ b/src/context.cc
@@ -57,13 +57,11 @@ Context::~Context()
 	Initialize context from a module argument list and a evaluation context
 	which may pass variables which will be preferred over default values.
 */
-void Context::setVariables(const std::vector<std::string> &argnames, 
-													 const std::vector<Expression*> &argexpr,
+void Context::setVariables(const AssignmentList &args,
 													 const EvalContext *evalctx)
 {
-	for (size_t i=0; i<argnames.size(); i++) {
-		set_variable(argnames[i], i < argexpr.size() && argexpr[i] ? 
-								 argexpr[i]->evaluate(this->parent) : Value());
+	BOOST_FOREACH(const Assignment &arg, args) {
+		set_variable(arg.first, arg.second ? arg.second->evaluate(this->parent) : Value());
 	}
 
 	if (evalctx) {
@@ -72,7 +70,7 @@ void Context::setVariables(const std::vector<std::string> &argnames,
 			const std::string &name = evalctx->eval_arguments[i].first;
 			const Value &val = evalctx->eval_arguments[i].second;
 			if (name.empty()) {
-				if (posarg < argnames.size()) this->set_variable(argnames[posarg++], val);
+				if (posarg < args.size()) this->set_variable(args[posarg++].first, val);
 			} else {
 				this->set_variable(name, val);
 			}
@@ -158,8 +156,8 @@ void Context::dump(const AbstractModule *mod, const ModuleInstantiation *inst)
 		const Module *m = dynamic_cast<const Module*>(mod);
 		if (m) {
 			PRINT("  module args:");
-			BOOST_FOREACH(const std::string &arg, m->argnames) {
-				PRINTB("    %s = %s", arg % variables[arg]);
+			BOOST_FOREACH(const Assignment &arg, m->definition_arguments) {
+				PRINTB("    %s = %s", arg.first % variables[arg.first]);
 			}
 		}
 	}
diff --git a/src/context.h b/src/context.h
index 282a940..51fc45c 100644
--- a/src/context.h
+++ b/src/context.h
@@ -5,6 +5,7 @@
 #include <vector>
 #include <boost/unordered_map.hpp>
 #include "value.h"
+#include "typedefs.h"
 
 class Context
 {
@@ -15,8 +16,7 @@ public:
 	virtual Value evaluate_function(const std::string &name, const class EvalContext *evalctx) const;
 	virtual class AbstractNode *evaluate_module(const class ModuleInstantiation &inst, const EvalContext *evalctx) const;
 
-	void setVariables(const std::vector<std::string> &argnames, 
-										const std::vector<class Expression*> &argexpr, 
+	void setVariables(const AssignmentList &args,
 										const class EvalContext *evalctx = NULL);
 
 	void set_variable(const std::string &name, const Value &value);
diff --git a/src/control.cc b/src/control.cc
index 446e47e..d47eec0 100644
--- a/src/control.cc
+++ b/src/control.cc
@@ -140,7 +140,7 @@ AbstractNode *ControlModule::evaluate(const Context *ctx, const ModuleInstantiat
 	{
 		std::stringstream msg;
 		msg << "ECHO: ";
-		for (size_t i = 0; i < inst->argnames.size(); i++) {
+		for (size_t i = 0; i < inst->arguments.size(); i++) {
 			if (i > 0) msg << ", ";
 			if (!evalctx->eval_arguments[i].first.empty()) msg << evalctx->eval_arguments[i].first << " = ";
 			msg << evalctx->eval_arguments[i].second;
diff --git a/src/evalcontext.cc b/src/evalcontext.cc
index 39e5aae..b7566e3 100644
--- a/src/evalcontext.cc
+++ b/src/evalcontext.cc
@@ -31,8 +31,8 @@ void EvalContext::dump(const AbstractModule *mod, const ModuleInstantiation *ins
 		const Module *m = dynamic_cast<const Module*>(mod);
 		if (m) {
 			PRINT("  module args:");
-			BOOST_FOREACH(const std::string &arg, m->argnames) {
-				PRINTB("    %s = %s", arg % variables[arg]);
+			BOOST_FOREACH(const Assignment &arg, m->definition_arguments) {
+				PRINTB("    %s = %s", arg.first % variables[arg.first]);
 			}
 		}
 	}
diff --git a/src/expr.cc b/src/expr.cc
index 1d7b440..7a8180f 100644
--- a/src/expr.cc
+++ b/src/expr.cc
@@ -128,9 +128,9 @@ Value Expression::evaluate(const Context *context) const
 	}
 	if (this->type == "F") {
 		EvalContext c(context);
-		for (size_t i=0; i < this->children.size(); i++) {
-			c.eval_arguments.push_back(std::make_pair(this->call_argnames[i], 
-																								this->children[i]->evaluate(context)));
+		for (size_t i=0; i < this->call_arguments.size(); i++) {
+			c.eval_arguments.push_back(std::make_pair(this->call_arguments[i].first, 
+																								this->call_arguments[i].second->evaluate(context)));
 		}
 		// Value::VectorType argvalues;
 		// std::transform(this->children.begin(), this->children.end(), 
@@ -183,10 +183,11 @@ std::string Expression::toString() const
 	}
 	else if (this->type == "F") {
 		stream << this->call_funcname << "(";
-		for (size_t i=0; i < this->children.size(); i++) {
+		for (size_t i=0; i < this->call_arguments.size(); i++) {
+			const Assignment &arg = this->call_arguments[i];
 			if (i > 0) stream << ", ";
-			if (!this->call_argnames[i].empty()) stream << this->call_argnames[i]  << " = ";
-			stream << *this->children[i];
+			if (!arg.first.empty()) stream << arg.first  << " = ";
+			stream << *arg.second;
 		}
 		stream << ")";
 	}
diff --git a/src/expression.h b/src/expression.h
index 2919b78..06becc0 100644
--- a/src/expression.h
+++ b/src/expression.h
@@ -4,6 +4,7 @@
 #include <string>
 #include <vector>
 #include "value.h"
+#include "typedefs.h"
 
 class Expression
 {
@@ -14,7 +15,7 @@ public:
 	std::string var_name;
 
 	std::string call_funcname;
-	std::vector<std::string> call_argnames;
+	AssignmentList call_arguments;
 
 	// Boolean: ! && ||
 	// Operators: * / % + -
diff --git a/src/func.cc b/src/func.cc
index ecd1f87..f2c9835 100644
--- a/src/func.cc
+++ b/src/func.cc
@@ -34,6 +34,7 @@
 #include <algorithm>
 #include "stl-utils.h"
 #include "printutils.h"
+#include <boost/foreach.hpp>
 
 /*
  Random numbers
@@ -75,14 +76,14 @@ std::string AbstractFunction::dump(const std::string &indent, const std::string
 
 Function::~Function()
 {
-	std::for_each(this->argexpr.begin(), this->argexpr.end(), del_fun<Expression>());
+	BOOST_FOREACH(const Assignment &arg, this->definition_arguments) delete arg.second;
 	delete expr;
 }
 
 Value Function::evaluate(const Context *ctx, const EvalContext *evalctx) const
 {
 	Context c(ctx);
-	c.setVariables(argnames, argexpr, evalctx);
+	c.setVariables(definition_arguments, evalctx);
 	return expr ? expr->evaluate(&c) : Value();
 }
 
@@ -90,10 +91,11 @@ std::string Function::dump(const std::string &indent, const std::string &name) c
 {
 	std::stringstream dump;
 	dump << indent << "function " << name << "(";
-	for (size_t i=0; i < argnames.size(); i++) {
+	for (size_t i=0; i < definition_arguments.size(); i++) {
+		const Assignment &arg = definition_arguments[i];
 		if (i > 0) dump << ", ";
-		dump << argnames[i];
-		if (argexpr[i]) dump << " = " << *argexpr[i];
+		dump << arg.first;
+		if (arg.second) dump << " = " << *arg.second;
 	}
 	dump << ") = " << *expr << ";\n";
 	return dump.str();
diff --git a/src/function.h b/src/function.h
index bd7c329..a1fde3c 100644
--- a/src/function.h
+++ b/src/function.h
@@ -2,6 +2,7 @@
 #define FUNCTION_H_
 
 #include "value.h"
+#include "typedefs.h"
 #include <string>
 #include <vector>
 
@@ -29,8 +30,7 @@ public:
 class Function : public AbstractFunction
 {
 public:
-	std::vector<std::string> argnames;
-	std::vector<class Expression*> argexpr;
+	AssignmentList definition_arguments;
 
 	Expression *expr;
 
diff --git a/src/import.cc b/src/import.cc
index 283bbe6..ba42b0a 100644
--- a/src/import.cc
+++ b/src/import.cc
@@ -65,20 +65,22 @@ public:
 
 AbstractNode *ImportModule::evaluate(const Context *ctx, const ModuleInstantiation *inst, const EvalContext *evalctx) const
 {
-	std::vector<std::string> argnames;
-	argnames += "file", "layer", "convexity", "origin", "scale";
-	std::vector<Expression*> argexpr;
+	AssignmentList args;
+	args += Assignment("file", NULL), Assignment("layer", NULL), Assignment("convexity", NULL), Assignment("origin", NULL), Assignment("scale", NULL);
 
+  // FIXME: This is broken. Tag as deprecated and fix
 	// Map old argnames to new argnames for compatibility
+#if 0
 	std::vector<std::string> inst_argnames = inst->argnames;
 	for (size_t i=0; i<inst_argnames.size(); i++) {
 		if (inst_argnames[i] == "filename") inst_argnames[i] = "file";
 		if (inst_argnames[i] == "layername") inst_argnames[i] = "layer";
 	}
+#endif
 
 	Context c(ctx);
 	c.setDocumentPath(evalctx->documentPath());
-	c.setVariables(argnames, argexpr, evalctx);
+	c.setVariables(args, evalctx);
 #if 0 && DEBUG
 	c.dump(this, inst);
 #endif
diff --git a/src/lexer.l b/src/lexer.l
index 4dff654..6766abc 100644
--- a/src/lexer.l
+++ b/src/lexer.l
@@ -26,6 +26,7 @@
 
 %{
 
+#include "typedefs.h"
 #include "handle_dep.h"
 #include "printutils.h"
 #include "parsersettings.h"
diff --git a/src/linearextrude.cc b/src/linearextrude.cc
index de728f7..f4c1112 100644
--- a/src/linearextrude.cc
+++ b/src/linearextrude.cc
@@ -52,12 +52,11 @@ AbstractNode *LinearExtrudeModule::evaluate(const Context *ctx, const ModuleInst
 {
 	LinearExtrudeNode *node = new LinearExtrudeNode(inst);
 
-	std::vector<std::string> argnames;
-	argnames += "file", "layer", "height", "origin", "scale", "center", "twist", "slices";
-	std::vector<Expression*> argexpr;
+	AssignmentList args;
+	args += Assignment("file", NULL), Assignment("layer", NULL), Assignment("height", NULL), Assignment("origin", NULL), Assignment("scale", NULL), Assignment("center", NULL), Assignment("twist", NULL), Assignment("slices", NULL);
 
 	Context c(ctx);
-	c.setVariables(argnames, argexpr, evalctx);
+	c.setVariables(args, evalctx);
 
 	node->fn = c.lookup_variable("$fn").toDouble();
 	node->fs = c.lookup_variable("$fs").toDouble();
diff --git a/src/modcontext.cc b/src/modcontext.cc
index 3280108..7d123b8 100644
--- a/src/modcontext.cc
+++ b/src/modcontext.cc
@@ -26,7 +26,7 @@ ModuleContext::~ModuleContext()
 
 void ModuleContext::setModule(const Module &module, const EvalContext *evalctx)
 {
-	this->setVariables(module.argnames, module.argexpr, evalctx);
+	this->setVariables(module.definition_arguments, evalctx);
 	this->evalctx = evalctx;
 
 	// FIXME: Don't access module members directly
@@ -131,8 +131,8 @@ void ModuleContext::dump(const AbstractModule *mod, const ModuleInstantiation *i
 		const Module *m = dynamic_cast<const Module*>(mod);
 		if (m) {
 			PRINT("  module args:");
-			BOOST_FOREACH(const std::string &arg, m->argnames) {
-				PRINTB("    %s = %s", arg % variables[arg]);
+			BOOST_FOREACH(const Assignment &arg, m->definition_arguments) {
+				PRINTB("    %s = %s", arg.first % variables[arg.first]);
 			}
 		}
 	}
diff --git a/src/module.cc b/src/module.cc
index d1e574d..7d83975 100644
--- a/src/module.cc
+++ b/src/module.cc
@@ -62,8 +62,8 @@ std::string AbstractModule::dump(const std::string &indent, const std::string &n
 
 ModuleInstantiation::~ModuleInstantiation()
 {
-	BOOST_FOREACH (Expression *v, argexpr) delete v;
-	BOOST_FOREACH (ModuleInstantiation *v, children) delete v;
+	BOOST_FOREACH(const Assignment &arg, this->arguments) delete arg.second;
+	BOOST_FOREACH(ModuleInstantiation *v, children) delete v;
 }
 
 IfElseModuleInstantiation::~IfElseModuleInstantiation()
@@ -89,10 +89,11 @@ std::string ModuleInstantiation::dump(const std::string &indent) const
 	std::stringstream dump;
 	dump << indent;
 	dump << modname + "(";
-	for (size_t i=0; i < argnames.size(); i++) {
+	for (size_t i=0; i < this->arguments.size(); i++) {
+		const Assignment &arg = this->arguments[i];
 		if (i > 0) dump << ", ";
-		if (!argnames[i].empty()) dump << argnames[i] << " = ";
-		dump << *argexpr[i];
+		if (!arg.first.empty()) dump << arg.first << " = ";
+		dump << *arg.second;
 	}
 	if (children.size() == 0) {
 		dump << ");\n";
@@ -112,10 +113,10 @@ std::string ModuleInstantiation::dump(const std::string &indent) const
 AbstractNode *ModuleInstantiation::evaluate_instance(const Context *ctx) const
 {
 	EvalContext c(ctx);
-	for (size_t i=0; i<argnames.size(); i++) {
-		c.eval_arguments.push_back(std::make_pair(argnames[i], 
-																							i < argexpr.size() && argexpr[i] ? 
-																							argexpr[i]->evaluate(ctx) : 
+	BOOST_FOREACH(const Assignment &arg, this->arguments) {
+		c.eval_arguments.push_back(std::make_pair(arg.first,
+																							arg.second ? 
+																							arg.second->evaluate(ctx) : 
 																							Value()));
 	}
 	c.children = this->children;
@@ -150,7 +151,7 @@ std::vector<AbstractNode*> IfElseModuleInstantiation::evaluateElseChildren(const
 
 Module::~Module()
 {
-	BOOST_FOREACH (const AssignmentContainer::value_type &v, assignments) delete v.second;
+	BOOST_FOREACH (const Assignment &v, assignments) delete v.second;
 	BOOST_FOREACH (FunctionContainer::value_type &f, functions) delete f.second;
 	BOOST_FOREACH (AbstractModuleContainer::value_type &m, modules) delete m.second;
 	BOOST_FOREACH (ModuleInstantiation *v, children) delete v;
@@ -181,10 +182,11 @@ std::string Module::dump(const std::string &indent, const std::string &name) con
 	std::string tab;
 	if (!name.empty()) {
 		dump << indent << "module " << name << "(";
-		for (size_t i=0; i < argnames.size(); i++) {
+		for (size_t i=0; i < this->definition_arguments.size(); i++) {
+			const Assignment &arg = this->definition_arguments[i];
 			if (i > 0) dump << ", ";
-			dump << argnames[i];
-			if (argexpr[i]) dump << " = " << *argexpr[i];
+			dump << arg.first;
+			if (arg.second) dump << " = " << *arg.second;
 		}
 		dump << ") {\n";
 		tab = "\t";
diff --git a/src/module.h b/src/module.h
index 17f0c59..ace3c1b 100644
--- a/src/module.h
+++ b/src/module.h
@@ -6,6 +6,7 @@
 #include <list>
 #include <boost/unordered_map.hpp>
 #include "value.h"
+#include "typedefs.h"
 
 class ModuleInstantiation
 {
@@ -27,8 +28,7 @@ public:
 	bool isHighlight() const { return this->tag_highlight; }
 	bool isRoot() const { return this->tag_root; }
 
-	std::vector<std::string> argnames;
-	std::vector<class Expression*> argexpr;
+	AssignmentList arguments;
 	std::vector<ModuleInstantiation*> children;
 
 	bool tag_root;
@@ -81,8 +81,8 @@ public:
 	bool handleDependencies();
 
 	std::list<std::string> assignments_var;
-	typedef boost::unordered_map<std::string, Expression*> AssignmentContainer;
-	AssignmentContainer assignments;
+	typedef boost::unordered_map<std::string, Expression*> AssignmentMap;
+	AssignmentMap assignments;
 
 	typedef boost::unordered_map<std::string, class AbstractFunction*> FunctionContainer;
 	FunctionContainer functions;
@@ -91,8 +91,7 @@ public:
 
 	std::vector<ModuleInstantiation*> children;
 
-	std::vector<std::string> argnames;
-	std::vector<Expression*> argexpr;
+	std::vector<Assignment> definition_arguments;
 
 protected:
 
diff --git a/src/parser.y b/src/parser.y
index 26bdba6..9b4f888 100644
--- a/src/parser.y
+++ b/src/parser.y
@@ -34,6 +34,7 @@
 #include <unistd.h>
 #endif
 
+#include "typedefs.h"
 #include "module.h"
 #include "expression.h"
 #include "value.h"
@@ -64,17 +65,6 @@ extern const char *parser_input_buffer;
 const char *parser_input_buffer;
 std::string parser_source_path;
 
-class ArgContainer {
-public: 
-	std::string argname;
-	Expression *argexpr;
-};
-class ArgsContainer {
-public:
-	std::vector<std::string> argnames;
-	std::vector<Expression*> argexpr;
-};
-
 %}
 
 %union {
@@ -85,8 +75,8 @@ public:
 	class ModuleInstantiation *inst;
 	std::vector<ModuleInstantiation*> *instvec;
 	class IfElseModuleInstantiation *ifelse;
-	class ArgContainer *arg;
-	class ArgsContainer *args;
+	Assignment *arg;
+	AssignmentList *args;
 }
 
 %token TOK_MODULE
@@ -168,8 +158,7 @@ statement:
 		module_stack.push_back(currmodule);
 		currmodule = new Module();
 		p->modules[$2] = currmodule;
-		currmodule->argnames = $4->argnames;
-		currmodule->argexpr = $4->argexpr;
+		currmodule->definition_arguments = *$4;
 		free($2);
 		delete $4;
 	} statement {
@@ -178,8 +167,7 @@ statement:
 	} |
 	TOK_FUNCTION TOK_ID '(' arguments_decl optional_commas ')' '=' expr {
 		Function *func = new Function();
-		func->argnames = $4->argnames;
-		func->argexpr = $4->argexpr;
+		func->definition_arguments = *$4;
 		func->expr = $8;
 		currmodule->functions[$2] = func;
 		free($2);
@@ -201,8 +189,7 @@ children_instantiation:
 if_statement:
 	TOK_IF '(' expr ')' children_instantiation {
 		$$ = new IfElseModuleInstantiation();
-		$$->argnames.push_back("");
-		$$->argexpr.push_back($3);
+		$$->arguments.push_back(Assignment("", $3));
                 $$->setPath(parser_source_path);
 
 		if ($$) {
@@ -279,8 +266,7 @@ module_instantiation_list:
 single_module_instantiation:
 	TOK_ID '(' arguments_call ')' {
 		$$ = new ModuleInstantiation($1);
-		$$->argnames = $3->argnames;
-		$$->argexpr = $3->argexpr;
+		$$->arguments = *$3;
                 $$->setPath(parser_source_path);
 		free($1);
 		delete $3;
@@ -448,8 +434,7 @@ expr:
 		$$ = new Expression();
 		$$->type = "F";
 		$$->call_funcname = $1;
-		$$->call_argnames = $3->argnames;
-		$$->children = $3->argexpr;
+		$$->call_arguments = *$3;
 		free($1);
 		delete $3;
 	} ;
@@ -470,61 +455,50 @@ vector_expr:
 
 arguments_decl:
 	/* empty */ {
-		$$ = new ArgsContainer();
+		$$ = new AssignmentList();
 	} |
 	argument_decl {
-		$$ = new ArgsContainer();
-		$$->argnames.push_back($1->argname);
-		$$->argexpr.push_back($1->argexpr);
+		$$ = new AssignmentList();
+		$$->push_back(*$1);
 		delete $1;
 	} |
 	arguments_decl ',' optional_commas argument_decl {
 		$$ = $1;
-		$$->argnames.push_back($4->argname);
-		$$->argexpr.push_back($4->argexpr);
+		$$->push_back(*$4);
 		delete $4;
 	} ;
 
 argument_decl:
 	TOK_ID {
-		$$ = new ArgContainer();
-		$$->argname = $1;
-		$$->argexpr = NULL;
+		$$ = new Assignment($1, NULL);
 		free($1);
 	} |
 	TOK_ID '=' expr {
-		$$ = new ArgContainer();
-		$$->argname = $1;
-		$$->argexpr = $3;
+		$$ = new Assignment($1, $3);
 		free($1);
 	} ;
 
 arguments_call:
 	/* empty */ {
-		$$ = new ArgsContainer();
+		$$ = new AssignmentList();
 	} |
 	argument_call {
-		$$ = new ArgsContainer();
-		$$->argnames.push_back($1->argname);
-		$$->argexpr.push_back($1->argexpr);
+		$$ = new AssignmentList();
+		$$->push_back(*$1);
 		delete $1;
 	} |
 	arguments_call ',' optional_commas argument_call {
 		$$ = $1;
-		$$->argnames.push_back($4->argname);
-		$$->argexpr.push_back($4->argexpr);
+		$$->push_back(*$4);
 		delete $4;
 	} ;
 
 argument_call:
 	expr {
-		$$ = new ArgContainer();
-		$$->argexpr = $1;
+		$$ = new Assignment("", $1);
 	} |
 	TOK_ID '=' expr {
-		$$ = new ArgContainer();
-		$$->argname = $1;
-		$$->argexpr = $3;
+		$$ = new Assignment($1, $3);
 		free($1);
 	} ;
 
diff --git a/src/primitives.cc b/src/primitives.cc
index 40e7e0b..184b40c 100644
--- a/src/primitives.cc
+++ b/src/primitives.cc
@@ -112,37 +112,36 @@ AbstractNode *PrimitiveModule::evaluate(const Context *ctx, const ModuleInstanti
 	node->center = false;
 	node->x = node->y = node->z = node->h = node->r1 = node->r2 = 1;
 
-	std::vector<std::string> argnames;
-	std::vector<Expression*> argexpr;
+	AssignmentList args;
 
 	switch (this->type) {
 	case CUBE:
-		argnames += "size", "center";
+		args += Assignment("size", NULL), Assignment("center", NULL);
 		break;
 	case SPHERE:
-		argnames += "r";
+		args += Assignment("r", NULL);
 		break;
 	case CYLINDER:
-		argnames += "h", "r1", "r2", "center";
+		args += Assignment("h", NULL), Assignment("r1", NULL), Assignment("r2", NULL), Assignment("center", NULL);
 		break;
 	case POLYHEDRON:
-		argnames += "points", "triangles", "convexity";
+		args += Assignment("points", NULL), Assignment("triangles", NULL), Assignment("convexity", NULL);
 		break;
 	case SQUARE:
-		argnames += "size", "center";
+		args += Assignment("size", NULL), Assignment("center", NULL);
 		break;
 	case CIRCLE:
-		argnames += "r";
+		args += Assignment("r", NULL);
 		break;
 	case POLYGON:
-		argnames += "points", "paths", "convexity";
+		args += Assignment("points", NULL), Assignment("paths", NULL), Assignment("convexity", NULL);
 		break;
 	default:
 		assert(false && "PrimitiveModule::evaluate(): Unknown node type");
 	}
 
 	Context c(ctx);
-	c.setVariables(argnames, argexpr, evalctx);
+	c.setVariables(args, evalctx);
 
 	node->fn = c.lookup_variable("$fn").toDouble();
 	node->fs = c.lookup_variable("$fs").toDouble();
diff --git a/src/projection.cc b/src/projection.cc
index 46add48..eeed411 100644
--- a/src/projection.cc
+++ b/src/projection.cc
@@ -48,12 +48,11 @@ AbstractNode *ProjectionModule::evaluate(const Context *ctx, const ModuleInstant
 {
 	ProjectionNode *node = new ProjectionNode(inst);
 
-	std::vector<std::string> argnames;
-	argnames += "cut";
-	std::vector<Expression*> argexpr;
+	AssignmentList args;
+	args += Assignment("cut", NULL);
 
 	Context c(ctx);
-	c.setVariables(argnames, argexpr, evalctx);
+	c.setVariables(args, evalctx);
 
 	Value convexity = c.lookup_variable("convexity", true);
 	Value cut = c.lookup_variable("cut", true);
diff --git a/src/render.cc b/src/render.cc
index 855e5e3..bb08c0c 100644
--- a/src/render.cc
+++ b/src/render.cc
@@ -45,12 +45,11 @@ AbstractNode *RenderModule::evaluate(const Context *ctx, const ModuleInstantiati
 {
 	RenderNode *node = new RenderNode(inst);
 
-	std::vector<std::string> argnames;
-	argnames += "convexity";
-	std::vector<Expression*> argexpr;
+	AssignmentList args;
+	args += Assignment("convexity", NULL);
 
 	Context c(ctx);
-	c.setVariables(argnames, argexpr, evalctx);
+	c.setVariables(args, evalctx);
 
 	Value v = c.lookup_variable("convexity");
 	if (v.type() == Value::NUMBER)
diff --git a/src/rotateextrude.cc b/src/rotateextrude.cc
index 29a873f..b6edb8b 100644
--- a/src/rotateextrude.cc
+++ b/src/rotateextrude.cc
@@ -52,12 +52,11 @@ AbstractNode *RotateExtrudeModule::evaluate(const Context *ctx, const ModuleInst
 {
 	RotateExtrudeNode *node = new RotateExtrudeNode(inst);
 
-	std::vector<std::string> argnames;
-	argnames += "file", "layer", "origin", "scale";
-	std::vector<Expression*> argexpr;
+	AssignmentList args;
+	args += Assignment("file", NULL), Assignment("layer", NULL), Assignment("origin", NULL), Assignment("scale", NULL);
 
 	Context c(ctx);
-	c.setVariables(argnames, argexpr, evalctx);
+	c.setVariables(args, evalctx);
 
 	node->fn = c.lookup_variable("$fn").toDouble();
 	node->fs = c.lookup_variable("$fs").toDouble();
diff --git a/src/surface.cc b/src/surface.cc
index 22da93d..d8fa422 100644
--- a/src/surface.cc
+++ b/src/surface.cc
@@ -75,12 +75,11 @@ AbstractNode *SurfaceModule::evaluate(const Context *ctx, const ModuleInstantiat
 	node->center = false;
 	node->convexity = 1;
 
-	std::vector<std::string> argnames;
-	argnames += "file", "center", "convexity";
-	std::vector<Expression*> argexpr;
+	AssignmentList args;
+	args += Assignment("file", NULL), Assignment("center", NULL), Assignment("convexity", NULL);
 
 	Context c(ctx);
-	c.setVariables(argnames, argexpr, evalctx);
+	c.setVariables(args, evalctx);
 
 	Value fileval = c.lookup_variable("file");
 	node->filename = inst->getAbsolutePath(fileval.isUndefined() ? "" : fileval.toString());
diff --git a/src/transform.cc b/src/transform.cc
index 6246a59..cc026fb 100644
--- a/src/transform.cc
+++ b/src/transform.cc
@@ -59,31 +59,30 @@ AbstractNode *TransformModule::evaluate(const Context *ctx, const ModuleInstanti
 
 	node->matrix = Transform3d::Identity();
 
-	std::vector<std::string> argnames;
-	std::vector<Expression*> argexpr;
+	AssignmentList args;
 
 	switch (this->type) {
 	case SCALE:
-		argnames += "v";
+		args += Assignment("v", NULL);
 		break;
 	case ROTATE:
-		argnames += "a", "v";
+		args += Assignment("a", NULL), Assignment("v", NULL);
 		break;
 	case MIRROR:
-		argnames += "v";
+		args += Assignment("v", NULL);
 		break;
 	case TRANSLATE:
-		argnames += "v";
+		args += Assignment("v", NULL);
 		break;
 	case MULTMATRIX:
-		argnames += "m";
+		args += Assignment("m", NULL);
 		break;
 	default:
 		assert(false);
 	}
 
 	Context c(ctx);
-	c.setVariables(argnames, argexpr, evalctx);
+	c.setVariables(args, evalctx);
 
 	if (this->type == SCALE)
 	{
diff --git a/src/typedefs.h b/src/typedefs.h
new file mode 100644
index 0000000..a6e9077
--- /dev/null
+++ b/src/typedefs.h
@@ -0,0 +1,10 @@
+#ifndef TYPEDEFS_H_
+#define TYPEDEFS_H_
+
+#include <string>
+#include <vector>
+
+typedef std::pair<std::string, class Expression*> Assignment;
+typedef std::vector<Assignment> AssignmentList;
+
+#endif