Builtin arguments: undef means not given; h/a aliases; linear_extrude default height 100

CLAUDE.md

@@ -730,7 +730,14 @@ grep for `ponytail:`.
   parameter names live in `builtinParamNames` (`registry.cpp`): each list is the union of real
   OpenSCAD's own `Parameters::parse` declaration and any extra name this port reads via `getArg`,
   so the port never warns about an argument it goes on to honour — **add to it whenever a builtin
-  gains a parameter**, or that parameter starts warning. Builtin *functions* deliberately have no
+  gains a parameter**, or that parameter starts warning. **An argument given as `undef` is not given**: `getArg`
+  returns the default for it, as every upstream builtin does (`if (v.isDefined())`). Wrappers
+  forward their own optional parameters as undef -- BOSL2's `rotate_extrude` override passes
+  `angle=angle`, and reading that as 0 degrees flattened every plain `rotate_extrude()` (#680).
+  Checked argument by argument against OpenSCAD 2026.02 (47 cases, `tests/test_undef_args.cpp`).
+  Aliases (`linear_extrude`'s `h`, `rotate_extrude`'s `a`) go through `getArgOrAlias`, which
+  warns `Specified both "height" and "h"` as upstream and lets the primary name win.
+  `linear_extrude`'s default height is 100, upstream's (it was 1). Builtin *functions* deliberately have no
   entries beyond `textmetrics`/`fontmetrics`: upstream reads their arguments positionally without
   `Parameters::parse`, so `sin(bogus=30)` warns about nothing there (verified against 2022.08.22)
   and warning here would be a divergence. Not ported: the reference's `argument X supplied more

include/openscad_cpp_evaluator/call_args.hpp

@@ -69,8 +69,20 @@ ResolvedCallArgs resolveCallArgs(Evaluator& ev, const std::vector<std::unique_pt
 // wins). `pos = std::nullopt` for an argument with no positional slot at
 // all (e.g. sphere's `d`, only ever named -- a later phase's need, plumbed
 // through now since the signature shape matters more than early callers).
+//
+// An argument given as undef counts as not given, as in every upstream
+// builtin (`if (v.isDefined()) ...`): rotate_extrude(angle=undef) is 360
+// degrees, not 0. It matters for wrappers that forward their own optional
+// parameters -- BOSL2's rotate_extrude override passes `angle=angle`, which
+// flattened every plain rotate_extrude() into its profile (#680).
 Value getArg(const CallArgs& args, std::optional<int> pos, const std::string& name, Value defaultValue = Value{});
 
+// getArg for a parameter with an alternative name (linear_extrude's
+// height/h, rotate_extrude's angle/a): `name` wins when both are given,
+// with upstream's warning.
+Value getArgOrAlias(Evaluator& ev, const oscad::Position* where, const CallArgs& args, std::optional<int> pos,
+                    const std::string& name, const std::string& alias, Value defaultValue);
+
 // Encodes a CallArgs as a single Value (positional -> a list indexed 0..N,
 // named -> an object) so a resolve function can carry a call's raw
 // arguments across into CSGParams (which only holds Value) for a generate

src/builtins/call_args.cpp

@@ -56,14 +56,31 @@ CallArgs resolveArgs(Evaluator& ev, const std::vector<std::unique_ptr<oscad::Arg
     return result;
 }
 
+namespace {
+bool isUndef(const Value& v) { return std::holds_alternative<std::monostate>(v); }
+} // namespace
+
 Value getArg(const CallArgs& args, std::optional<int> pos, const std::string& name, Value defaultValue) {
-    if (const Value* named = args.findNamed(name)) return *named;
+    if (const Value* named = args.findNamed(name); named && !isUndef(*named)) return *named;
     if (pos.has_value()) {
-        if (const Value* positional = args.findPositional(*pos)) return *positional;
+        if (const Value* positional = args.findPositional(*pos); positional && !isUndef(*positional))
+            return *positional;
     }
     return defaultValue;
 }
 
+Value getArgOrAlias(Evaluator& ev, const oscad::Position* where, const CallArgs& args, std::optional<int> pos,
+                    const std::string& name, const std::string& alias, Value defaultValue) {
+    const Value primary = getArg(args, pos, name, Value{});
+    const Value other = getArg(args, std::nullopt, alias, Value{});
+    if (!isUndef(primary)) {
+        if (!isUndef(other))
+            ev.warn("Specified both \"" + name + "\" and \"" + alias + "\"", where);
+        return primary;
+    }
+    return isUndef(other) ? defaultValue : other;
+}
+
 ResolvedCallArgs resolveCallArgs(Evaluator& ev, const std::vector<std::unique_ptr<oscad::Argument>>& arguments,
                                   EvalContext& ctx) {
     CallArgs args = resolveArgs(ev, arguments, ctx);

src/builtins/extrude.cpp

@@ -118,7 +118,9 @@ manifold::Manifold extrudeTwisted(const manifold::Polygons& polys, double height
 BuiltinWrapParams computeLinearExtrudeParams(Evaluator& ev, const oscad::ModularCall& node, EvalContext& ctx) {
     auto [args, effCtx] = resolveCallArgs(ev, node.arguments, ctx);
 
-    const double height = toDoubleLenient(getArg(args, 0, "height", Value{1.0}));
+    // 100 when not given, as upstream (the old 1 was a guess), and `h` as
+    // upstream's alias -- BOSL2's linear_extrude override forwards it.
+    const double height = toDoubleLenient(getArgOrAlias(ev, &node.position(), args, 0, "height", "h", Value{100.0}));
     const bool center = truthy(getArg(args, std::nullopt, "center", Value{false}));
     const double twist = toDoubleLenient(getArg(args, std::nullopt, "twist", Value{0.0}));
     // Upstream's validate_integral: any finite number counts as given, and is
@@ -239,7 +241,7 @@ std::vector<ColoredBody> generateLinearExtrude(Evaluator& ev, const CSGParams& p
 BuiltinWrapParams computeRotateExtrudeParams(Evaluator& ev, const oscad::ModularCall& node, EvalContext& ctx) {
     auto [args, effCtx] = resolveCallArgs(ev, node.arguments, ctx);
 
-    const double angle = toDoubleLenient(getArg(args, 0, "angle", Value{360.0}));
+    const double angle = toDoubleLenient(getArgOrAlias(ev, &node.position(), args, 0, "angle", "a", Value{360.0}));
 
     CSGParams params;
     params["angle"] = Value{angle};

src/builtins/registry.cpp

@@ -125,8 +125,8 @@ const std::vector<std::string>* builtinParamNames(const std::string& name) {
         {"import",
           {"file", "layer", "convexity", "origin", "scale", "width", "height", "filename", "layername", "center", "dpi",
            "id", "class", "repair", "tolerance"}},
-        {"linear_extrude", {"height", "v", "scale", "center", "twist", "slices", "segments", "convexity"}},
-        {"rotate_extrude", {"angle", "start", "convexity"}},
+        {"linear_extrude", {"height", "h", "v", "scale", "center", "twist", "slices", "segments", "convexity"}},
+        {"rotate_extrude", {"angle", "a", "start", "convexity"}},
         {"projection", {"cut", "convexity"}},
         {"roof", {"method", "convexity"}},
         {"fill", {}},

tests/CMakeLists.txt

@@ -31,6 +31,7 @@ add_executable(oscad_eval_tests
   test_use.cpp
   test_coverage.cpp
   test_extrude_roof.cpp
+  test_undef_args.cpp
   test_discretizer.cpp
   test_surface.cpp
   test_dxf_svg_import.cpp

tests/test_undef_args.cpp

@@ -0,0 +1,100 @@
+// A builtin argument given as undef means "not given" (#680), and the
+// height/h and angle/a aliases, as upstream OpenSCAD -- each checked
+// against OpenSCAD 2026.02 before being written down here.
+//
+// Wrappers forward their own optional parameters: BOSL2's rotate_extrude
+// override passes angle=angle, undef when the user gave none, and taking
+// that undef as 0 degrees flattened every plain rotate_extrude() into its
+// profile.
+
+#include "test_helpers.hpp"
+
+#include <gtest/gtest.h>
+
+#include <string>
+#include <vector>
+
+using namespace oscadeval;
+using namespace oscadeval::test;
+
+namespace {
+
+struct Shape {
+    double volume;
+    manifold::Box box;
+};
+
+Shape shapeOf(const std::string& code) {
+    Evaluated e = evalSrc(code);
+    EXPECT_EQ(e.bodies.size(), 1u) << code;
+    if (e.bodies.empty() || !e.bodies[0].body.has_value()) return {0.0, {}};
+    return {e.bodies[0].body->Volume(), e.bodies[0].body->BoundingBox()};
+}
+
+void expectSameShape(const std::string& a, const std::string& b) {
+    const Shape x = shapeOf(a), y = shapeOf(b);
+    EXPECT_GT(x.volume, 0.0) << a;
+    EXPECT_NEAR(x.volume, y.volume, 1e-6) << a << " vs " << b;
+    EXPECT_NEAR(x.box.max.x, y.box.max.x, 1e-6) << a;
+    EXPECT_NEAR(x.box.max.y, y.box.max.y, 1e-6) << a;
+    EXPECT_NEAR(x.box.max.z, y.box.max.z, 1e-6) << a;
+    EXPECT_NEAR(x.box.min.x, y.box.min.x, 1e-6) << a;
+}
+
+std::vector<std::string> warningsFor(const std::string& code) {
+    std::vector<std::string> out;
+    Evaluated e = evalSrc(code, [&](const std::string& msg) {
+        if (msg.rfind("WARNING: ", 0) == 0) out.push_back(msg);
+    });
+    (void)e;
+    return out;
+}
+
+} // namespace
+
+// Every argument that took an explicit undef as a value rather than as absent.
+TEST(UndefArgs, AnUndefArgumentIsTheDefault) {
+    expectSameShape("rotate_extrude(angle=undef) translate([10,0]) square(5);",
+                    "rotate_extrude() translate([10,0]) square(5);");
+    expectSameShape("linear_extrude(height=undef) square(5);", "linear_extrude() square(5);");
+    expectSameShape("cylinder(h=undef, r=2);", "cylinder(r=2);");
+    expectSameShape("linear_extrude(1) square(size=undef);", "linear_extrude(1) square();");
+    expectSameShape("linear_extrude(1) text(\"A\", size=undef);", "linear_extrude(1) text(\"A\");");
+    expectSameShape("linear_extrude(1) text(\"AB\", spacing=undef);", "linear_extrude(1) text(\"AB\");");
+    // Positional undef too.
+    expectSameShape("rotate_extrude(undef) translate([10,0]) square(5);",
+                    "rotate_extrude() translate([10,0]) square(5);");
+}
+
+TEST(UndefArgs, AWrapperForwardingItsOwnOptionalAngleStillRevolvesFully) {
+    expectSameShape("module re(angle) rotate_extrude(angle=angle) children();\n"
+                    "re() translate([10,0]) square(5);",
+                    "rotate_extrude() translate([10,0]) square(5);");
+}
+
+TEST(UndefArgs, LinearExtrudeDefaultsToAHeightOfOneHundred) {
+    EXPECT_NEAR(shapeOf("linear_extrude() square(5);").box.max.z, 100.0, 1e-9);
+    const Shape centred = shapeOf("linear_extrude(center=true) square(5);");
+    EXPECT_NEAR(centred.box.min.z, -50.0, 1e-9);
+    EXPECT_NEAR(centred.box.max.z, 50.0, 1e-9);
+}
+
+TEST(UndefArgs, HIsHeightAndAIsAngle) {
+    EXPECT_NEAR(shapeOf("linear_extrude(h=7) square(5);").box.max.z, 7.0, 1e-9);
+    expectSameShape("rotate_extrude(a=90) translate([10,0]) square(5);",
+                    "rotate_extrude(angle=90) translate([10,0]) square(5);");
+    EXPECT_TRUE(warningsFor("linear_extrude(h=7) square(5);").empty());
+    EXPECT_TRUE(warningsFor("rotate_extrude(a=90) translate([10,0]) square(5);").empty());
+}
+
+TEST(UndefArgs, BothNamesGivenWarnsAndThePrimaryWins) {
+    EXPECT_NEAR(shapeOf("linear_extrude(height=3, h=7) square(5);").box.max.z, 3.0, 1e-9);
+    const auto w = warningsFor("linear_extrude(height=3, h=7) square(5);");
+    ASSERT_EQ(w.size(), 1u);
+    EXPECT_NE(w[0].find("Specified both \"height\" and \"h\""), std::string::npos) << w[0];
+    expectSameShape("rotate_extrude(angle=45, a=90) translate([10,0]) square(5);",
+                    "rotate_extrude(angle=45) translate([10,0]) square(5);");
+    const auto wa = warningsFor("rotate_extrude(angle=45, a=90) translate([10,0]) square(5);");
+    ASSERT_EQ(wa.size(), 1u);
+    EXPECT_NE(wa[0].find("Specified both \"angle\" and \"a\""), std::string::npos) << wa[0];
+}