Gmt module: Conversion function for GMTPen now using new parameter reading scheme and error reporting.

modules/gmt/modgmt_func.h

@@ -174,6 +174,8 @@ using Base2Coord =Base2Struct<struct gmt_coord>;
 using Base2Region=Base2Struct<struct gmt_region>;
 using Base2Proj  =Base2Struct<struct gmt_projection>;
 using Base2Color =Base2Struct<struct gmt_color>;
+using Base2Dash  =Base2Struct<struct gmt_dash>;
+using Base2Pen   =Base2Struct<struct gmt_pen>;
 
 // Simple aliases of convertors with default values
 using Base2StringD=Base2StructD<std::string>;
@@ -194,7 +196,37 @@ class Base2CoordD: public DefaultConverter<Base2Coord>
  Base2CoordD(double d):DefaultConverter<Base2Coord>(Def(d)) {}
 };
 
-// Convertors for double non-negative value
+// Convertor with default value for gmt_color. Added constructor for creating default value from double argument
+class Base2ColorD: public DefaultConverter<Base2Color>
+{
+ static ValueType Def(double d)
+ {
+  ValueType v;
+  std::string fake;
+  v.Convert(d,fake);
+  return v;
+ }
+ public:
+ using ValueType=DefaultConverter<Base2Color>::ValueType;
+ Base2ColorD(double d):DefaultConverter<Base2Color>(Def(d)) {}
+};
+
+// Convertor with default value for gmt_dash. Default value is always no dash.
+class Base2DashD: public DefaultConverter<Base2Dash>
+{
+ static ValueType Def()
+ {
+  ValueType v;
+  v.Clear();
+  return v;
+ }
+ public:
+ using ValueType=DefaultConverter<Base2Dash>::ValueType;
+ Base2DashD():DefaultConverter<Base2Dash>(Def()) {}
+};
+
+
+// Convertors for double positive value
 class Base2Pos: public Base2Double
 {
  public:
@@ -211,6 +243,23 @@ class Base2Pos: public Base2Double
 };
 using Base2PosD=DefaultConverter<Base2Pos>;
 
+// Convertors for double non-negative value
+class Base2NonNeg: public Base2Double
+{
+ public:
+ double Convert(const ObjectBase* ob, bool* res, std::string& err)
+ {
+  double t=Base2Double::Convert(ob,res,err);
+  if(res && t<0)
+  {
+   *res=false;
+   err="Value mast be non-negative";
+  }
+  return t;
+ }
+};
+using Base2NonNegD=DefaultConverter<Base2NonNeg>;
+
 // Convertors for double values which must be in some interval
 template<int32_t Min, int32_t Max>
 class Base2InRange: public Base2Double
@@ -837,9 +886,6 @@ class Convert2Struct<struct gmt_color, ObjectList>
  }
 };
 
-// Helper types
-typedef SearchParameterWDefO<double,DoubleDefaultVal<>,false,PMin<0> > Base2Width;
-typedef SearchParameter<double,false,PMin<0> > BaseM2Width;
 
 // Converting List to GMTPen
 /*
@@ -860,91 +906,53 @@ class Convert2Struct<struct gmt_pen, ObjectList>
 {
  public:
 
- struct gmt_pen operator()(const ObjectList* input, bool* issuc) const
+ struct gmt_pen operator()(const ObjectList* input, bool* issuc, std::string& err) const
  {
   struct gmt_pen p;
-  auto size=input->Size();
 
-  if(1==size) // Cases 1, 2 and 4
+  if(1==input->Size()) // Cases 1, 2 and 4
   {
-   Base2Pen pen(input,0);
+   Base2Pen pen;
    bool suc=true;
-   p=pen(&suc);
+   p=pen.Convert(input->At(0),&suc,err);
    if(!suc) goto fail; // Conversion failed
    return p;
   }
 
-  // Case 3
-  {
-   bool casevalid=false;
-   bool upd;
-   {
-    BaseMT2Pen updarg(input,"pen","p");
-    bool suc=true;
-    p=updarg(&upd,&suc);
-    if(upd && !suc) goto fail; // Conversion failed or too many arguments
-   }
-
-   if(!upd)
+  // Case 5 and 6
   {
-    // default pen is solid black 1mm width
-    p.width=gmt_pen::default_width;
-    p.color.Convert(0);
-    p.dash.Clear();
-   }
+   OPosPar<Base2NonNegD> width("width",gmt_pen::default_width);
+   OPosPar<Base2ColorD> color("color",0.0);
+   OPosPar<Base2DashD> dash("dash");
 
-   {
-    BaseM2Width w(input,"w","width");
-    if(w.Exist())
-    {
-     bool suc=true;
-     p.width=w(&suc);
-     if(!suc) goto fail; // Parsing error
-     casevalid=true;
-    }
-   }
-
-   // Color
-   {
-    BaseMT2Color color(input,"color","c");
-    if(color.Exist())
-    {
-     bool suc=true;
-     p.color=color(&suc);
-     if(!suc) goto fail;  // Parsing error
-     casevalid=true;
-    }
+   ParsePositionalParameters params(input,width,color,dash);
+   if(!params) goto case3; // May be case3 will work
+   p.color=color;
+   p.dash=dash;
+   p.dash.width=p.width=width;
+   return p;
   }
 
-   // Dash
-   {
-    BaseMT2Dash dash(input,"dash","d");
-    if(dash.Exist())
+  // Case 3
+  case3:
   {
-     bool suc=true;
-     p.dash=dash(&suc);
-     if(!suc) goto fail;  // Parsing error
+    bool upd;
+   ONFPar<Base2Pen,ObjectGMTPen> pen("pen");
+   ONFPar<Base2ColorD,ObjectGMTColor> color("color",0.0);
+   ONFPar<Base2DashD,ObjectGMTDash> dash("dash");
+   ONPar<Base2NonNegD> width("width",gmt_pen::default_width);
+
+   {ParseNamedParameters params(input,color,pen,dash,width); if(!params) {err=params.Error(); goto fail;} } // Fail to parse by variant 3
+
+   upd=pen.Exist();
+   if(upd) p=pen;
+   if(color.Exist() || !upd) p.color=color;
+   if(dash.Exist()  || !upd) p.dash=dash;
+   if(width.Exist() || !upd) p.width=width;
    p.dash.width=p.width;
-     casevalid=true;
-    }
-   }
-
-   if(casevalid || upd) return p; // Pen created or updated
-  }
 
-  // Case 5 and 6
-  if(2==size || 3==size)
-  {
-   Base2Width w(input,0);
-   Base2Color c(input,1);
-   Base2Dash d(input,2);
-   bool suc=true;
-   p.width=w(&suc);
-   p.color=c(&suc);
-   if(!suc) goto fail; // Something wrong
-   p.dash=d(&suc,p.width);
-   if(!suc) goto fail; // Something wrong
-   return p;
+   if(color.Exist() || dash.Exist() || width.Exist() || upd) return p; // Pen created or updated
+   err="Specify at least one of color, dash or width";
   }
 
   fail: