jpayne@68: "Implement Idle Shell history mechanism with History class"
jpayne@68: 
jpayne@68: from idlelib.config import idleConf
jpayne@68: 
jpayne@68: 
jpayne@68: class History:
jpayne@68:     ''' Implement Idle Shell history mechanism.
jpayne@68: 
jpayne@68:     store - Store source statement (called from pyshell.resetoutput).
jpayne@68:     fetch - Fetch stored statement matching prefix already entered.
jpayne@68:     history_next - Bound to <<history-next>> event (default Alt-N).
jpayne@68:     history_prev - Bound to <<history-prev>> event (default Alt-P).
jpayne@68:     '''
jpayne@68:     def __init__(self, text):
jpayne@68:         '''Initialize data attributes and bind event methods.
jpayne@68: 
jpayne@68:         .text - Idle wrapper of tk Text widget, with .bell().
jpayne@68:         .history - source statements, possibly with multiple lines.
jpayne@68:         .prefix - source already entered at prompt; filters history list.
jpayne@68:         .pointer - index into history.
jpayne@68:         .cyclic - wrap around history list (or not).
jpayne@68:         '''
jpayne@68:         self.text = text
jpayne@68:         self.history = []
jpayne@68:         self.prefix = None
jpayne@68:         self.pointer = None
jpayne@68:         self.cyclic = idleConf.GetOption("main", "History", "cyclic", 1, "bool")
jpayne@68:         text.bind("<<history-previous>>", self.history_prev)
jpayne@68:         text.bind("<<history-next>>", self.history_next)
jpayne@68: 
jpayne@68:     def history_next(self, event):
jpayne@68:         "Fetch later statement; start with ealiest if cyclic."
jpayne@68:         self.fetch(reverse=False)
jpayne@68:         return "break"
jpayne@68: 
jpayne@68:     def history_prev(self, event):
jpayne@68:         "Fetch earlier statement; start with most recent."
jpayne@68:         self.fetch(reverse=True)
jpayne@68:         return "break"
jpayne@68: 
jpayne@68:     def fetch(self, reverse):
jpayne@68:         '''Fetch statement and replace current line in text widget.
jpayne@68: 
jpayne@68:         Set prefix and pointer as needed for successive fetches.
jpayne@68:         Reset them to None, None when returning to the start line.
jpayne@68:         Sound bell when return to start line or cannot leave a line
jpayne@68:         because cyclic is False.
jpayne@68:         '''
jpayne@68:         nhist = len(self.history)
jpayne@68:         pointer = self.pointer
jpayne@68:         prefix = self.prefix
jpayne@68:         if pointer is not None and prefix is not None:
jpayne@68:             if self.text.compare("insert", "!=", "end-1c") or \
jpayne@68:                     self.text.get("iomark", "end-1c") != self.history[pointer]:
jpayne@68:                 pointer = prefix = None
jpayne@68:                 self.text.mark_set("insert", "end-1c")  # != after cursor move
jpayne@68:         if pointer is None or prefix is None:
jpayne@68:             prefix = self.text.get("iomark", "end-1c")
jpayne@68:             if reverse:
jpayne@68:                 pointer = nhist  # will be decremented
jpayne@68:             else:
jpayne@68:                 if self.cyclic:
jpayne@68:                     pointer = -1  # will be incremented
jpayne@68:                 else:  # abort history_next
jpayne@68:                     self.text.bell()
jpayne@68:                     return
jpayne@68:         nprefix = len(prefix)
jpayne@68:         while 1:
jpayne@68:             pointer += -1 if reverse else 1
jpayne@68:             if pointer < 0 or pointer >= nhist:
jpayne@68:                 self.text.bell()
jpayne@68:                 if not self.cyclic and pointer < 0:  # abort history_prev
jpayne@68:                     return
jpayne@68:                 else:
jpayne@68:                     if self.text.get("iomark", "end-1c") != prefix:
jpayne@68:                         self.text.delete("iomark", "end-1c")
jpayne@68:                         self.text.insert("iomark", prefix)
jpayne@68:                     pointer = prefix = None
jpayne@68:                 break
jpayne@68:             item = self.history[pointer]
jpayne@68:             if item[:nprefix] == prefix and len(item) > nprefix:
jpayne@68:                 self.text.delete("iomark", "end-1c")
jpayne@68:                 self.text.insert("iomark", item)
jpayne@68:                 break
jpayne@68:         self.text.see("insert")
jpayne@68:         self.text.tag_remove("sel", "1.0", "end")
jpayne@68:         self.pointer = pointer
jpayne@68:         self.prefix = prefix
jpayne@68: 
jpayne@68:     def store(self, source):
jpayne@68:         "Store Shell input statement into history list."
jpayne@68:         source = source.strip()
jpayne@68:         if len(source) > 2:
jpayne@68:             # avoid duplicates
jpayne@68:             try:
jpayne@68:                 self.history.remove(source)
jpayne@68:             except ValueError:
jpayne@68:                 pass
jpayne@68:             self.history.append(source)
jpayne@68:         self.pointer = None
jpayne@68:         self.prefix = None
jpayne@68: 
jpayne@68: 
jpayne@68: if __name__ == "__main__":
jpayne@68:     from unittest import main
jpayne@68:     main('idlelib.idle_test.test_history', verbosity=2, exit=False)