zachariahreed / Pyterminfo

pyterminfo is a parser for terminfo-style terminal descriptions. Roughly, it provides equivalent functionality of the ncurses functions tigetflag, tigetnum, tigetstr, and, tparm. The API presented is different though and hopefully more "pythonic".

An example shows basic usage:

import pyterminfo
  
# loads capabilities for $TERM
t = pyterminfo.terminfo()
    
t.os                  # a boolean capability
t.cols                # a numeric capability
t.sgr0                # a string capability
t.setaf(6)            # a parameterized-string capability
t.set_a_foreground(6) # long names work as well

By default, string capabilities are strs (or functions returning a str). While not strictly correct, it can be convenient. Passing binary=True to pyterminfo.terminfo causes string capabilities to be bytes based.

Finally, a note about pyterminfo's implementation. Typically, parameterized-string capabilities are implemented in a manner similiar to printf (parsing the format string on each invokation). Here, parameterized-string capabilities are implemented through generation of python bytecode. For example, from the capability:

setab=\E[%?%p1%{8}%<%t4%p1%d%e%p1%{16}%<%t10%p1%{8}%-%d%e48;5;%p1%d%;m,

the following is generated (in str mode):

  1           0 LOAD_CONST               0 #str.join
              3 LOAD_CONST               1 ('\x1b[')
              6 LOAD_FAST                0 (a1)
              9 LOAD_CONST               2 (8)
             12 COMPARE_OP               0 (<)
             15 POP_JUMP_IF_FALSE       33
             18 LOAD_CONST               3 ('4')
             21 LOAD_CONST               4 (<class 'str'>)
             24 LOAD_FAST                0 (a1)
             27 CALL_FUNCTION            1 (1 positional, 0 keyword pair)
             30 JUMP_FORWARD            43 (to 76)
        >>   33 LOAD_FAST                0 (a1)
             36 LOAD_CONST               5 (16)
             39 COMPARE_OP               0 (<)
             42 POP_JUMP_IF_FALSE       64
             45 LOAD_CONST               6 ('10')
             48 LOAD_CONST               4 (<class 'str'>)
             51 LOAD_FAST                0 (a1)
             54 LOAD_CONST               2 (8)
             57 BINARY_SUBTRACT
             58 CALL_FUNCTION            1 (1 positional, 0 keyword pair)
             61 JUMP_FORWARD            12 (to 76)
        >>   64 LOAD_CONST               7 ('48;5;')
             67 LOAD_CONST               4 (<class 'str'>)
             70 LOAD_FAST                0 (a1)
             73 CALL_FUNCTION            1 (1 positional, 0 keyword pair)
        >>   76 LOAD_CONST               8 ('m')
             79 BUILD_TUPLE              4
             82 CALL_FUNCTION            1 (1 positional, 0 keyword pair)
             85 RETURN_VALUE

The transformation from format string to bytecode happens in serveral stages which can be visualized by the curious. For the above, we can render:

High Level	Low Level

pyterminfo depends on .