evaluation function

[calc.git] / parser.c

diff --git a/parser.c b/parser.c
index 0caa750c65020c7f490c3da51ed64b7a82e8a0b5..02443079228e3385b361b5e2f027152ad48f18ad 100644 (file)
--- a/parser.c
+++ b/parser.c
@@ -1,4 +1,5 @@
 #include <malloc.h>
+#include <math.h>
 #include <stdlib.h>
 
 #include "debug.h"
@@ -270,7 +271,6 @@ void print_element (element_t *root, int level)
 
     switch (root->func) {
     case Val: func = "Value"; break;
-    case Set: func = "Set"; break;
     case Add: func = "Addition"; break;
     case Sub: func = "Subtraction"; break;
     case Mul: func = "Multiplication"; break;
@@ -298,4 +298,67 @@ void print_element (element_t *root, int level)
     }
 }
 
+/* evaluate element tree */
+
+double evaluate_element (element_t *root)
+{
+    double op0 = 0, op1 = 0;
+
+    if ((root == NULL) || (root == ERROR_OP)) {
+        VERBOSE (WARNING, PRINTOUT ("error while evaluating\n"));
+        return 0;
+    }
+
+    switch (root->func) {
+    case Val:
+        if (root->ops[0]) {
+            return evaluate_element (root->ops[0]);
+        } else {
+            return root->value;
+        }
+        break;
+    case Add:
+    case Sub:
+    case Mul:
+    case Div:
+    case Pow:
+        if (root->ops[1]) {
+            op1 = evaluate_element (root->ops[1]);
+        } else {
+            VERBOSE (WARNING, PRINTOUT ("error while evaluating (op[1])\n"));
+            return 0;
+        }
+        /* fallthrough */
+    case Sqr:
+    case Cos:
+    case Sin:
+    case Atn:
+    case Log:
+    case Exp:
+        if (root->ops[0]) {
+            op0 = evaluate_element (root->ops[0]);
+        } else {
+            VERBOSE (WARNING, PRINTOUT ("error while evaluating (op[0])\n"));
+            return 0;
+        }
+    }
+
+    switch (root->func) {
+    case Add: return op0 + op1;
+    case Sub: return op0 - op1;
+    case Mul: return op0 * op1;
+    case Div: return op0 / op1;
+    case Pow: return pow (op0, op1);
+    case Sqr: return sqrt (op0);
+    case Cos: return cos (op0);
+    case Sin: return sin (op0);
+    case Atn: return atan (op0);
+    case Log: return log (op0);
+    case Exp: return exp (op0);
+    default: break;
+    }
+
+    return 0;
+}
+
 /* vim: set ts=4 sw=4 et: */