[gnome-calculator/60-split-out-a-backend-library] gcalc: implemented solving constants

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit 0017454c82364d1f3071e7d60ce2b9d246d7af5e
Author: Daniel Espinosa Ortiz <esodan gmail com>
Date:   Thu Jan 3 17:53:31 2019 -0600

    gcalc: implemented solving constants

 gcalc/gcalc-gconstant.vala      |  3 +++
 gcalc/gcalc-gmath-equation.vala | 11 ++++++++++-
 gcalc/gcalc-gpolynomial.vala    |  2 +-
 gcalc/gcalc-gsolver.vala        | 13 +++++++++++--
 gcalc/gcalc-gterm.vala          |  3 ++-
 gcalc/gcalc-term.vala           | 10 ++++------
 tests/gcalc-solving-basic.vala  | 26 ++++++++++++++++++++++++++
 7 files changed, 57 insertions(+), 11 deletions(-)
---
diff --git a/gcalc/gcalc-gconstant.vala b/gcalc/gcalc-gconstant.vala
index e95c9b00..9d54b4f0 100644
--- a/gcalc/gcalc-gconstant.vala
+++ b/gcalc/gcalc-gconstant.vala
@@ -108,5 +108,8 @@ public class GCalc.GConstant : GExpression, Constant {
     }
     return "%g".printf (real ());
   }
+  public override Result solve () {
+    return new GResult (this) as Result;
+  }
 }
 
diff --git a/gcalc/gcalc-gmath-equation.vala b/gcalc/gcalc-gmath-equation.vala
index 56c82981..96b865ff 100644
--- a/gcalc/gcalc-gmath-equation.vala
+++ b/gcalc/gcalc-gmath-equation.vala
@@ -18,5 +18,14 @@
  * Authors:
  *      Daniel Espinosa <esodan gmail com>
  */
-public class GCalc.GMathEquation : GExpression, MathEquation {}
+public class GCalc.GMathEquation : GExpression, MathEquation {
+  public override Result solve () {
+    if (expressions.get_n_items () == 0) {
+      var err = new GErrorResult ("No expressions found in equation");
+      return new GResult.with_error ((Expression) new GExpression (), (ErrorResult) err) as Result;
+    }
+    var e = expressions.get_item (0) as Expression;
+    return e.solve ();
+  }
+}
 
diff --git a/gcalc/gcalc-gpolynomial.vala b/gcalc/gcalc-gpolynomial.vala
index 09f3e550..cc7abaeb 100644
--- a/gcalc/gcalc-gpolynomial.vala
+++ b/gcalc/gcalc-gpolynomial.vala
@@ -34,7 +34,7 @@ public class GCalc.GPolynomial : GExpression, Polynomial {
           continue;
         }
         try {
-          current.sum (t);
+          current = current.sum (t) as Term;
         } catch (GLib.Error err) {
           var nerr = new GErrorResult (err.message);
           return new GResult.with_error ((Expression) new GExpression (), (ErrorResult) nerr) as Result;
diff --git a/gcalc/gcalc-gsolver.vala b/gcalc/gcalc-gsolver.vala
index 8a90e0da..c3cffadf 100644
--- a/gcalc/gcalc-gsolver.vala
+++ b/gcalc/gcalc-gsolver.vala
@@ -31,10 +31,19 @@ public class GCalc.GSolver : Object, Solver {
     Result res;
     try {
       p.parse (str, equation_manager);
-      res = new GResult ((Expression) equation_manager.equations.get_item (0)) as Result; // FIXME: This 
should return a constant object
+      if (equation_manager.equations.get_n_items () == 0) {
+        var err = new GErrorResult ("No equations found after parsing");
+        res = new GResult.with_error ((Expression) new GExpression (), (ErrorResult) err) as Result;
+      }
+      var eq = equation_manager.equations.get_item (0) as MathEquation;
+      if (eq == null) {
+        var err = new GErrorResult ("No equations found after parsing");
+        res = new GResult.with_error ((Expression) new GExpression (), (ErrorResult) err) as Result;
+      }
+      res = eq.solve ();
     } catch (GLib.Error e) {
       var err = new GErrorResult (e.message);
-      res = new GResult.with_error ((Expression) new GExpression (), (ErrorResult) err) as Result; // FIXME: 
This should return a constant object
+      res = new GResult.with_error ((Expression) new GExpression (), (ErrorResult) err) as Result;
     }
     return res;
   }
diff --git a/gcalc/gcalc-gterm.vala b/gcalc/gcalc-gterm.vala
index 3998c7f8..8bb18227 100644
--- a/gcalc/gcalc-gterm.vala
+++ b/gcalc/gcalc-gterm.vala
@@ -18,5 +18,6 @@
  * Authors:
  *      Daniel Espinosa <esodan gmail com>
  */
-public class GCalc.GTerm : GExpression, Term {}
+public class GCalc.GTerm : GExpression, Term {
+}
 
diff --git a/gcalc/gcalc-term.vala b/gcalc/gcalc-term.vala
index 258ba529..2167ee3f 100644
--- a/gcalc/gcalc-term.vala
+++ b/gcalc/gcalc-term.vala
@@ -40,12 +40,10 @@ public interface GCalc.Term : Object, Expression {
         if (current == null) {
           current = e;
           first = false;
-        } else {
-          if (current is Constant) {
-            if (current_operator != null) {
-              if (e is Minus && e is Multiply) {
-                current = (current as Constant).multiply (e as Constant);
-              }
+        } else if (current is Constant) {
+          if (current_operator != null) {
+            if (e is Minus && e is Multiply) {
+              current = (current as Constant).multiply (e as Constant);
             }
           }
         }
diff --git a/tests/gcalc-solving-basic.vala b/tests/gcalc-solving-basic.vala
index 6489772f..76372fdf 100644
--- a/tests/gcalc-solving-basic.vala
+++ b/tests/gcalc-solving-basic.vala
@@ -76,6 +76,32 @@ class Tests {
       assert (c3.real () == -10.0);
       assert (c3.imag () == -15.0);
     });
+    Test.add_func ("/gcalc/solve/constant",
+    ()=>{
+      try {
+        var parser = new Parser ();
+        var eqman = new GMathEquationManager ();
+        parser.parse ("1", eqman);
+        assert (eqman.equations.get_n_items () == 1);
+        var eq = eqman.equations.get_item (0) as MathEquation;
+        assert (eq != null);
+        var e = eq.expressions.get_item (0) as Polynomial;
+        assert (e != null);
+        var t = e.expressions.get_item (0) as Term;
+        assert (t != null);
+        var c = t.expressions.get_item (0) as Constant;
+        assert (c != null);
+        var res = c.solve ();
+        assert (res != null);
+        assert (res.expression != null);
+        var rc = res.expression as Constant;
+        assert (rc != null);
+        message ("Constant Result: %s", rc.to_string ());
+        assert (rc.real () == 1.0);
+      } catch (GLib.Error e) {
+        warning ("Error: %s", e.message);
+      }
+    });
     return Test.run ();
   }
 }