Initial implementation of commands extension module.

discord/ext/commands/view.py

@@ -0,0 +1,167 @@
+# -*- coding: utf-8 -*-
+"""
+The MIT License (MIT)
+
+Copyright (c) 2015-2016 Rapptz
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+"""
+
+from .errors import BadArgument
+
+class StringView:
+    def __init__(self, buffer):
+        self.index = 0
+        self.buffer = buffer
+        self.end = len(buffer)
+        self.previous = 0
+
+    @property
+    def current(self):
+        return None if self.eof else self.buffer[self.index]
+
+    @property
+    def eof(self):
+        return self.index >= self.end
+
+    def undo(self):
+        self.index = self.previous
+
+    def skip_ws(self):
+        pos = 0
+        while not self.eof:
+            try:
+                current = self.buffer[self.index + pos]
+                if not current.isspace():
+                    break
+                pos += 1
+            except IndexError:
+                break
+
+        self.previous = self.index
+        self.index += pos
+        return self.previous != self.index
+
+    def skip_string(self, string):
+        strlen = len(string)
+        if self.buffer[self.index:self.index + strlen] == string:
+            self.previous = self.index
+            self.index += strlen
+            return True
+        return False
+
+    def read_rest(self):
+        result = self.buffer[self.index:]
+        self.previous = self.index
+        self.index = self.end
+        return result
+
+    def read(self, n):
+        result = self.buffer[self.index:self.index + n]
+        self.previous = self.index
+        self.index += n
+        return result
+
+    def get(self):
+        try:
+            result = self.buffer[self.index + 1]
+        except IndexError:
+            result = None
+
+        self.previous = self.index
+        self.index += 1
+        return result
+
+    def get_word(self):
+        pos = 0
+        while not self.eof:
+            try:
+                current = self.buffer[self.index + pos]
+                if current.isspace():
+                    break
+                pos += 1
+            except IndexError:
+                break
+        self.previous = self.index
+        result = self.buffer[self.index:self.index + pos]
+        self.index += pos
+        return result
+
+    def __repr__(self):
+        return '<StringView pos: {0.index} prev: {0.previous} end: {0.end} eof: {0.eof}>'.format(self)
+
+# Parser
+
+def quoted_word(view):
+    current = view.current
+
+    if current is None:
+        return None
+
+    is_quoted = current == '"'
+    result = [] if is_quoted else [current]
+
+    while not view.eof:
+        current = view.get()
+        if not current:
+            if is_quoted:
+                # unexpected EOF
+                raise BadArgument('Expected closing "')
+            return ''.join(result)
+
+        # currently we accept strings in the format of "hello world"
+        # to embed a quote inside the string you must escape it: "a \"world\""
+        if current == '\\':
+            next_char = view.get()
+            if not next_char:
+                # string ends with \ and no character after it
+                if is_quoted:
+                    # if we're quoted then we're expecting a closing quote
+                    raise BadArgument('Expected closing "')
+                # if we aren't then we just let it through
+                return ''.join(result)
+
+            if next_char == '"':
+                # escaped quote
+                result.append('"')
+            else:
+                # different escape character, ignore it
+                view.undo()
+                result.append(current)
+            continue
+
+        # closing quote
+        if current == '"':
+            next_char = view.get()
+            valid_eof = not next_char or next_char.isspace()
+            if is_quoted:
+                if not valid_eof:
+                    raise BadArgument('Expected space after closing quotation')
+
+                # we're quoted so it's okay
+                return ''.join(result)
+            else:
+                # we aren't quoted
+                raise BadArgument('Unexpected quote mark in non-quoted string')
+
+        if current.isspace() and not is_quoted:
+            # end of word found
+            return ''.join(result)
+
+        result.append(current)