[gjs: 1/4] Add calc.js from GNU Seed

[Philip Chimento <pchimento src gnome org>]

commit 2c8ea8ede89dfd634efe79c4d7892b1aef6c945c
Author: William Barath <w_barath hotmail com>
Date:   Mon Apr 23 22:36:52 2018 +0000

    Add calc.js from GNU Seed

 examples/calc.js | 137 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 137 insertions(+)
---
diff --git a/examples/calc.js b/examples/calc.js
new file mode 100644
index 00000000..f8f8b5ab
--- /dev/null
+++ b/examples/calc.js
@@ -0,0 +1,137 @@
+#!/usr/bin/env seed
+
+Gdk = imports.gi.Gdk;
+Gtk = imports.gi.Gtk;
+GLib = imports.gi.GLib;
+
+Gtk.init(Seed.argv);
+
+var calc_val = "";
+
+function update_display(){
+    label.set_markup("<span size='30000'>" + calc_val + "</span>");
+
+    if(calc_val === ""){
+       label.set_markup("<span size='30000'>0</span>");
+    }
+}
+
+function clear(button){
+    calc_val = "";
+    update_display();
+}
+
+function backspace(button){
+    calc_val = calc_val.substring(0, calc_val.length - 1);
+    update_display();
+}
+
+function pressed_equals(button){
+    calc_val = calc_val.replace("sin", "Math.sin");
+    calc_val = calc_val.replace("cos", "Math.cos");
+    calc_val = calc_val.replace("tan", "Math.tan");
+    calc_val = eval(calc_val) + "";
+    // Avoid rediculous amounts of precision from toString.
+    if (calc_val == Math.floor(calc_val))
+       calc_val = Seed.sprintf("%d", calc_val);
+    else
+       calc_val = Seed.sprintf("%.4f", calc_val);
+    label.set_markup("<span size='30000'>" + calc_val + "</span>");
+}
+
+function pressed_operator(button){
+    calc_val += button.label;
+    update_display();
+}
+
+function pressed_number(button){
+    calc_val = (((calc_val === 0) ? "" : calc_val) + button.label);
+    update_display();
+}
+
+function swap_sign(button){
+    calc_val = ((calc_val[0] == "-") ?
+               calc_val.substring(1) : "-" + calc_val);
+    update_display();
+}
+
+function random_num(){
+    calc_val = Math.floor(Math.random() * 1000) + "";
+    update_display();
+}
+
+function pack_buttons(buttons, vbox){
+    var hbox = new Gtk.HBox();
+
+    hbox.homogeneous = true;
+
+    vbox.pack_start(hbox, true, true, 2);
+
+    for(i = 0; i <= 4; i++){
+       hbox.pack_start(buttons[i], true, true, 1);
+    }
+}
+
+function create_button(str, func){
+    var btn = new Gtk.Button({label:str});
+    btn.signal.clicked.connect(func);
+    return btn;
+}
+
+function create_buttons(){
+    var vbox = new Gtk.VBox();
+
+    vbox.homogeneous = true;
+
+    pack_buttons([     create_button("(", pressed_number),
+                       create_button("←", backspace),
+                       create_button("↻", random_num),
+                       create_button("Clr", clear),
+                       create_button("±", swap_sign)], vbox);
+
+
+    pack_buttons([     create_button(")", pressed_number),
+                       create_button("7", pressed_number),
+                       create_button("8", pressed_number),
+                       create_button("9", pressed_number),
+                       create_button("/", pressed_operator)], vbox);
+
+    pack_buttons([     create_button("sin(", pressed_number),
+                       create_button("4", pressed_number),
+                       create_button("5", pressed_number),
+                       create_button("6", pressed_number),
+                       create_button("*", pressed_operator)], vbox);
+
+    pack_buttons([     create_button("cos(", pressed_number),
+                       create_button("1", pressed_number),
+                       create_button("2", pressed_number),
+                       create_button("3", pressed_number),
+                       create_button("-", pressed_operator)], vbox);
+
+    pack_buttons([     create_button("tan(", pressed_number),
+                       create_button("0", pressed_number),
+                       create_button(".", pressed_number),
+                       create_button("=", pressed_equals),
+                       create_button("+", pressed_operator)], vbox);
+
+    return vbox;
+}
+
+var window = new Gtk.Window({title: "Calculator", resizable: false});
+
+window.resize(250, 250);
+window.signal.hide.connect(Gtk.main_quit);
+window.opacity = 0.95;
+
+var label = new Gtk.Label({label: ""});
+label.set_alignment(1,0);
+update_display();
+
+var mainvbox = new Gtk.VBox();
+mainvbox.pack_start(label, false, true, 1);
+mainvbox.pack_start(new Gtk.HSeparator(), false, true, 5);
+mainvbox.pack_start(create_buttons(), true, true, 2);
+
+window.add(mainvbox);
+window.show_all();
+Gtk.main();
\ No newline at end of file