summary refs log tree commit diff
path: root/Functions/Misc/zcalc
blob: 78a48b9b02e7afdfb0b77d24cd2a608acd7e46ec (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
#!/usr/local/bin/zsh -i
#
# Zsh calculator.  Understands most ordinary arithmetic expressions.
# Line editing and history are available. A blank line or `q' quits.
#
# Runs as a script or a function.  If used as a function, the history
# is remembered for reuse in a later call (and also currently in the
# shell's own history).  There are various problems using this as a
# script, so a function is recommended.
#
# The prompt shows a number for the current line.  The corresponding
# result can be referred to with $<line-no>, e.g.
#   1> 32 + 10
#   42
#   2> $1 ** 2
#   1764
# The set of remembered numbers is primed with anything given on the
# command line.  For example,
#   zcalc '2 * 16'
#   1> 32                     # printed by function
#   2> $1 + 2                 # typed by user
#   34
#   3> 
# Here, 32 is stored as $1.  This works in the obvious way for any
# number of arguments.
#
# If the mathfunc library is available, probably understands most system
# mathematical functions.  The left parenthesis must be adjacent to the
# end of the function name, to distinguish from shell parameters
# (translation: to prevent the maintainers from having to write proper
# lookahead parsing).  For example,
#   1> sqrt(2)
#   1.4142135623730951
# is right, but `sqrt (2)' will give you an error.
#
# You can do things with parameters like
#   1> pi = 4.0 * atan(1)
# too.  These go into global parameters, so be careful.  You can declare
# local variables, however:
#   1> local pi
# but note this can't appear on the same line as a calculation.  Don't
# use the variables listed in the `local' and `integer' lines below
# (translation: I can't be bothered to provide a sandbox).
#
# Some constants are already available: (case sensitive as always):
#   PI     pi, i.e. 3.1415926545897931
#   E      e, i.e. 2.7182818284590455
#
# You can also change the output base.
#   1> [#16]
#   1>
# Changes the default output to hexadecimal with numbers preceded by `16#'.
# Note the line isn't remembered.
#   2> [##16]
#   2>
# Change the default output base to hexadecimal with no prefix.
#   3> [#]
# Reset the default output base.
#
# This is based on the builtin feature that you can change the output base
# of a given expression.  For example,
#   1> [##16]  32 + 20 / 2
#   2A
#   2> 
# prints the result of the calculation in hexadecimal.
#
# You can't change the default input base, but the shell allows any small
# integer as a base:
#   1> 2#1111
#   15
#   2> [##13] 13#6 * 13#9
#   42
# and the standard C-like notation with a leading 0x for hexadecimal is
# also understood.  However, leading 0 for octal is not understood --- it's
# too confusing in a calculator.  Use 8#777 etc.
#
#
# To do:
# - separate zcalc history from shell history using arrays --- or allow
#   zsh to switch internally to and from array-based history.
# - allow setting number of decimal places for display, scientific notation, 
#   etc.

emulate -L zsh
setopt extendedglob

local line latest base defbase match mbegin mend psvar
integer num

zmodload -i zsh/mathfunc 2>/dev/null

: ${ZCALCPROMPT="%1v> "}

# Supply some constants.
float PI E
(( PI = 4 * atan(1), E = exp(1) ))

for (( num = 1; num <= $#; num++ )); do
  # Make sure all arguments have been evaluated.
  # The `$' before the second argv forces string rather than numeric
  # substitution.
  (( argv[$num] = $argv[$num] ))
  print "$num> $argv[$num]"
done

psvar[1]=$num
while vared -cehp "${(%)ZCALCPROMPT}" line; do
  [[ -z $line ]] && break
  # special cases
  # Set default base if `[#16]' or `[##16]' etc. on its own.
  # Unset it if `[#]' or `[##]'.
  if [[ $line = (#b)[[:blank:]]#('[#'(\#|)(<->|)']')[[:blank:]]#(*) ]]; then
    if [[ -z $match[4] ]]; then
      if [[ -z $match[3] ]]; then
	defbase=
      else
	defbase=$match[1]
      fi
      print -s -- $line
      line=
      continue
    else
      base=
    fi
  else
    base=$defbase
  fi
  # Exit if `q' on its own.
  [[ $line = [[:blank:]]#q[[:blank:]]# ]] && return 0

  print -s -- $line
  if [[ $line = [[:blank:]]#local([[:blank:]]##*|) ]]; then
    eval $line
  else
    # Latest value is stored as a string, because it might be floating
    # point or integer --- we don't know till after the evaluation, and
    # arrays always store scalars anyway.
    # 
    # Since it's a string, we'd better make sure we know which
    # base it's in, so don't change that until we actually print it.
    eval "latest=\$(( $line ))"
    argv[num++]=$latest
    psvar[1]=$num
    if [[ -z $base ]]; then
      print -- $latest
    else
      print -- $(( $base $latest ))
    fi
  fi
  line=
done

return 0