Add model to type system

fcad/fcad.scad

@@ -2,8 +2,8 @@ include <cube.scad>;
 include <cylinder.scad>;
 include <draw.scad>;
 include <math.scad>;
+include <model.scad>;
 include <obj_util.scad>;
 include <sphere.scad>;
-include <struct.scad>;
 include <translate.scad>;
 include <types.scad>;

fcad/model.scad

@@ -1,12 +1,20 @@
 /// model:
-///   kKeyPoints "points" fPoints(): [ [x, y, z], ... ]
-///   kKeyFaces "faces" fFaces(): [ [ pointIdx, ... ], ... ]
+///   fKeyType "type" fType(): fTypeModel "model"
+///   fKeyPoints "points" fPoints(): [ [x, y, z], ... ]
+///   fKeyFaces "faces" fFaces(): [ [ pointIdx, ... ], ... ]
+
+fTypeModel = "model";
+
+function fIsModel(x) = (
+  fType(x) == fTypeModel
+);
 
 fKeyPoints = "points";
 fKeyFaces = "faces";
 
 function fModel(points, faces) = (
   [
+    [fKeyType, fTypeModel],
     [fKeyPoints, points],
     [fKeyFaces, faces],
   ]

fcad/types.scad

@@ -1,3 +1,5 @@
+fKeyType = "type";
+
 fTypeUndef = "undef";
 fTypeInt = "int";
 fTypeFloat = "float";
@@ -12,6 +14,7 @@ function fType(x) = (
   : abs(x) + 1 > abs(x) ? fTypeFloat
   : str(x) == x ? fTypeString
   : str(x) == "false" || str(x) == "true" ? fTypeBoolean
+  : fMapLookup(fKeyType, x) ? fMapLookup(fKeyType, x)
   : (x[0] == x[0]) && len(x) != undef ? fTypeVector
   : fTypeUnknown
 );
@@ -40,6 +43,7 @@ function fIsVector(x) = (
   fType(x) == fTypeVector
 );
 
+// Helpers
 function fMapLookup(key, model) = (
   [for (pair = model)
    let (iter_key = pair[0],