added log.scad

src/log.scad

@@ -0,0 +1,72 @@
+/**
+* log.scad
+*
+* A log module which supports simple level configurations and color titles.
+* 
+* @copyright Justin Lin, 2017
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib-log.html
+*
+**/
+
+/*
+   The accepted values are "OFF" (-1), "INFO" (20), 
+   "WARNING" (30), "ERROR" (40) or positive integers.
+*/
+$log_level = "INFO";
+
+module log(level = "INFO", level_color) {
+    default_level_ints = [
+        ["OFF", -1],
+        ["INFO", 20], 
+        ["WARNING", 30],
+        ["ERROR", 40]
+    ];
+    
+    default_level_colors = [
+        ["INFO", "green"], 
+        ["WARNING", "orange"],
+        ["ERROR", "red"]
+    ];    
+
+    /*
+        The built-in lookup function require integer keys. 
+        I overwrite it so that using string keys is ok.
+    */
+    function lookup(key, mappings, i = 0) = 
+        i == len(mappings) ? key : (
+            key == mappings[i][0] ? 
+                mappings[i][1] :
+                lookup(key, mappings, i + 1)
+        );
+
+    if($log_level != "OFF") {            
+        argu_level = lookup(level, default_level_ints);
+        golbal_level = lookup(
+            $log_level == undef ? "INFO" : $log_level,
+            default_level_ints
+        );
+
+        if(argu_level >= golbal_level) {
+            c = level_color == undef ? lookup(level, default_level_colors) : level_color;
+            lv = str(len(level) == undef ? "LEVEL " : "", level);
+            
+            // level text
+            echo(
+                str(
+                    "<b>", 
+                        "<font color='", c, "'>", 
+                            lv, 
+                        "</font>", 
+                    "</b>"
+                )
+            );
+            
+            // echo 
+            for(i = [0:$children - 1]) {
+                children(i);
+            }
+        }    
+    } 
+}