#! /usr/bin/env python
#
def s_to_l4 ( s ):

#*****************************************************************************80
#
## S_TO_L4 reads a logical value from a string.
#
#  Discussion:
#
#    There are several ways of representing logical data that this routine
#    recognizes:
#
#      False   True
#      -----   ----
#
#      0       1
#      F       T
#      f       t
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    21 November 2015
#
#  Author:
#
#    John Burkardt
#
#  Parameters:
#
#    Input, string S, the string to be read.
#
#    Output, bool L, the logical value read from the string.
#
  from sys import exit

  s_length = len ( s )

  for i in range ( 0, s_length ):

    if ( s[i] == '0' or s[i] == 'F' or s[i] == 'f' ):
      l = False
      return l
    elif ( s[i] == '1' or s[i] == 'T' or s[i] == 't' ):
      l = True
      return l

  print ( '' )
  print ( 'S_TO_L4 - Fatal error!' )
  print ( '  The input string did not contain logical data.' )
  exit ( 'S_TO_L4 - Fatal error!' )

def s_to_l4_test ( ):

#*****************************************************************************80
#
## S_TO_L4_TEST tests S_TO_L4.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    21 November 2015
#
#  Author:
#
#    John Burkardt
#
  test_num = 10

  import numpy as np

  s_test = [ \
    '0      ', \
    'F      ', \
    'f      ', \
    '1      ', \
    'T      ', \
    't      ', \
    '  0    ', \
    '  1  0 ', \
    '  01   ', \
    '  Talse' ]

  print ( '' )
  print ( 'S_TO_L4_TEST' )
  print ( '  S_TO_L4 reads logical data from a string.' )
  print ( '' )
  print ( '        S   L4' )
  print ( '' )

  for test in range ( 0, test_num ):
    s = s_test[test]
    l4 = s_to_l4 ( s )
    print ( '  "%7s"  %s' % ( s, l4 ) )
#
#  Terminate.
#
  print ( '' )
  print ( 'S_TO_L4_TEST' )
  print ( '  Normal end of execution.' )
  return

if ( __name__ == '__main__' ):
  from timestamp import timestamp
  timestamp ( )
  s_to_l4_test ( )
  timestamp ( )