Add wish.py for generating wrappers around plugins.

wish.py

@@ -0,0 +1,140 @@
+#!/usr/bin/env python3
+"""
+Generate function wrappers from config for wish.
+
+wish.py works by writing plugins which are isolated from the global plugins.
+It assigns all the config to relevant variables inside a wrapper. e.g.
+
+If the config file is
+
+```
+|left|
+[plugin]
+name = date
+format = %F
+```
+
+wish.py creates a wrapper around date as 0_date where 0 is the index of plugin.
+Inside the wrapper, in each function, it sets WISH_DATE_FORMAT="%F" and
+WISH_DATE_BG=$WISH_0_DATE_BG (same for FG), so the plugin sees its config as
+defined in the config file. After calling the plugin's relevant function, it
+sets WISH_0_DATE_BG=$WISH_DATE_BG (same for FG) in case, the plugin has changed
+it). This allows multiple instances of the same plugin to coexist with
+different config and different themes.
+"""
+
+from os.path import isfile
+import shlex
+import sys
+
+import ginie
+
+
+def parse_core(core):
+    "Parses a core block"
+    config = core["config"]
+    for key in core["config"]:
+        print("WISH_{}={}".format(key.upper(), shlex.quote(config[key])))
+
+
+def parse_plugin(plugin, plugin_idx):
+    "Parses a plugin and writes a wrapper around it"
+    config = plugin["config"]
+    try:
+        plugin_name = config["name"].strip().lower()
+        config["name"] = plugin_name
+    except KeyError:
+        return False
+
+    keys_from_source = ("BG", "FG")
+    for j in ("start", "end", "set_colors", "main"):
+        print("function wish_{}_{}_{}()".format(plugin_idx, plugin_name, j))
+        print("{")
+        for key in keys_from_source:
+            print("\tlocal WISH_{0}_{2}=$WISH_{1}_{0}_{2}".format(
+                plugin_name.upper(),
+                plugin_idx,
+                key.upper()
+            ))
+        for key in config:
+            if key == "name":
+                continue
+            print("\tlocal WISH_{}_{}={}".format(plugin_name.upper(),
+                                                 key.upper(),
+                                                 shlex.quote(config[key])))
+        print("\twish_{}_{} $*".format(plugin_name, j))
+        print("\tlocal err=$?")
+        for key in keys_from_source:
+            print("\tWISH_{1}_{0}_{2}=$WISH_{0}_{2}".format(
+                plugin_name.upper(),
+                plugin_idx,
+                key.upper()
+            ))
+        print("\treturn $err")
+        print("}")
+    return True
+
+
+def print_plugin_list(name, array, always=False):
+    "Prints a list of plugins as a bash array"
+    if array or always:
+        print("{}=(".format(name))
+        for plugin in array:
+            print("\t" + plugin)
+        print(")")
+
+
+def main():
+    "Parse a config file passed as first argument"
+    config_file = []
+    for file_name in sys.argv[1:]:
+        if isfile(file_name):
+            with open(file_name) as file:
+                config_file += ginie.load(file)
+        else:
+            print("echo Invalid config file: {}".format(
+                shlex.quote(file_name)))
+
+    plugin_idx = 0
+    plugins_to_source = []
+    left_plugins = []
+    right_plugins = []
+    for i in config_file:
+        kind = i["type"]
+        name = i["name"]
+        # Parse core blocks outside a section.
+        # No other blocks outside a section need to be parsed for now.
+        if kind == "block" and name == "core":
+            parse_core(i)
+        elif kind == "section":
+            # All sections other than left and right are skipped.
+            if name not in ("left", "right"):
+                continue
+            for block in i["blocks"]:
+                if block["name"] == "core":
+                    parse_core(block)
+                elif block["name"] == "plugin" and parse_plugin(block,
+                                                                plugin_idx):
+                    plugin_name = "{}_{}".format(plugin_idx,
+                                                 block["config"]["name"])
+                    if name == "left":
+                        left_plugins.append(plugin_name)
+                    else:
+                        right_plugins.append(plugin_name)
+                    plugins_to_source.append(block["config"]["name"])
+                    plugin_idx += 1
+
+    print_plugin_list("WISH_PLUGINS", left_plugins)
+    print_plugin_list("WISH_RIGHT_PLUGINS", right_plugins)
+    print_plugin_list("WISH_PLUGINS_SOURCE", plugins_to_source)
+
+
+# Python 2 patch
+# TODO: Write a better patch for Python 2
+try:
+    shlex.quote
+except AttributeError:
+    shlex.quote = lambda x: x
+
+if __name__ == "__main__":
+    main()