1  "Implement Idle Shell history mechanism with History class"
       2  
       3  from idlelib.config import idleConf
       4  
       5  
       6  class ESC[4;38;5;81mHistory:
       7      ''' Implement Idle Shell history mechanism.
       8  
       9      store - Store source statement (called from pyshell.resetoutput).
      10      fetch - Fetch stored statement matching prefix already entered.
      11      history_next - Bound to <<history-next>> event (default Alt-N).
      12      history_prev - Bound to <<history-prev>> event (default Alt-P).
      13      '''
      14      def __init__(self, text):
      15          '''Initialize data attributes and bind event methods.
      16  
      17          .text - Idle wrapper of tk Text widget, with .bell().
      18          .history - source statements, possibly with multiple lines.
      19          .prefix - source already entered at prompt; filters history list.
      20          .pointer - index into history.
      21          .cyclic - wrap around history list (or not).
      22          '''
      23          self.text = text
      24          self.history = []
      25          self.prefix = None
      26          self.pointer = None
      27          self.cyclic = idleConf.GetOption("main", "History", "cyclic", 1, "bool")
      28          text.bind("<<history-previous>>", self.history_prev)
      29          text.bind("<<history-next>>", self.history_next)
      30  
      31      def history_next(self, event):
      32          "Fetch later statement; start with earliest if cyclic."
      33          self.fetch(reverse=False)
      34          return "break"
      35  
      36      def history_prev(self, event):
      37          "Fetch earlier statement; start with most recent."
      38          self.fetch(reverse=True)
      39          return "break"
      40  
      41      def fetch(self, reverse):
      42          '''Fetch statement and replace current line in text widget.
      43  
      44          Set prefix and pointer as needed for successive fetches.
      45          Reset them to None, None when returning to the start line.
      46          Sound bell when return to start line or cannot leave a line
      47          because cyclic is False.
      48          '''
      49          nhist = len(self.history)
      50          pointer = self.pointer
      51          prefix = self.prefix
      52          if pointer is not None and prefix is not None:
      53              if self.text.compare("insert", "!=", "end-1c") or \
      54                      self.text.get("iomark", "end-1c") != self.history[pointer]:
      55                  pointer = prefix = None
      56                  self.text.mark_set("insert", "end-1c")  # != after cursor move
      57          if pointer is None or prefix is None:
      58              prefix = self.text.get("iomark", "end-1c")
      59              if reverse:
      60                  pointer = nhist  # will be decremented
      61              else:
      62                  if self.cyclic:
      63                      pointer = -1  # will be incremented
      64                  else:  # abort history_next
      65                      self.text.bell()
      66                      return
      67          nprefix = len(prefix)
      68          while True:
      69              pointer += -1 if reverse else 1
      70              if pointer < 0 or pointer >= nhist:
      71                  self.text.bell()
      72                  if not self.cyclic and pointer < 0:  # abort history_prev
      73                      return
      74                  else:
      75                      if self.text.get("iomark", "end-1c") != prefix:
      76                          self.text.delete("iomark", "end-1c")
      77                          self.text.insert("iomark", prefix, "stdin")
      78                      pointer = prefix = None
      79                  break
      80              item = self.history[pointer]
      81              if item[:nprefix] == prefix and len(item) > nprefix:
      82                  self.text.delete("iomark", "end-1c")
      83                  self.text.insert("iomark", item, "stdin")
      84                  break
      85          self.text.see("insert")
      86          self.text.tag_remove("sel", "1.0", "end")
      87          self.pointer = pointer
      88          self.prefix = prefix
      89  
      90      def store(self, source):
      91          "Store Shell input statement into history list."
      92          source = source.strip()
      93          if len(source) > 2:
      94              # avoid duplicates
      95              try:
      96                  self.history.remove(source)
      97              except ValueError:
      98                  pass
      99              self.history.append(source)
     100          self.pointer = None
     101          self.prefix = None
     102  
     103  
     104  if __name__ == "__main__":
     105      from unittest import main
     106      main('idlelib.idle_test.test_history', verbosity=2, exit=False)