User Commands - shell (1)
NAME
shell(1f) - shell for demonstrating major modules in libGPF.a (LICENSE:PD)
CONTENTS
Synopsis
Description
Options
Usage
Example
Author
License
SYNOPSIS
shell expression| --help| --version|[ -replay][ -read FILENAME]
DESCRIPTION
Example command line interface with command line history, numeric expressions, if/else/elseif/endif logic, and Unix-like command parsing.
OPTIONS
--help display this help and exit --version output version information and exit
USAGE
At the command prompt the following example commands may be used:
#--------------------------------------------------------------------------# | command |exercises | description | #--------------------------------------------------------------------------# | r | M_HISTORY | enter history editor; | | | | ? will produce help | #--------------------------------------------------------------------------# | today format [-help] | M_TIME | display current time using | | | | fmtdate(3f) | #--------------------------------------------------------------------------# | if/else/elseif expression | M_LOGIC | conditionally process input | | | | lines | | endif | M_LOGIC | end IF block | #--------------------------------------------------------------------------# | set dump | M_CALCULATOR | dump currently defined | | | | variable names | | set funcs | M_CALCULATOR | describe functions available| | | | in expressions | | set nc() | JUOWN1/CALC_NC | display list of ncurses() | | | | functions | | set expression [-q] | M_CALCULATOR | anything else is assumed to | | | | be a numeric expression | | set | M_CALCULATOR | If no expression switch to | | | | calculator mode till "." is | | | | entered. | #--------------------------------------------------------------------------# | read file [-q] | M_KRACKEN | read from another input file| | test1 -x -y --help --version| M_KRACKEN | test of DISSECT(3f) | #--------------------------------------------------------------------------# | | M_PIXEL | pixel graphics | |prefsize: specify size of pixel array |vinit: initialize pixel array drawing module | |rect: draw line rectangle given two opposite corners |line: draw line between two points applying line width and color |polyline: draw lines between points |rmove2: relative move |move2: move current position |rdraw2: relative draw |draw2: draw a line from current position to specified point | |point2: Draw a point at x, y | |arc: draw a arc using current line width and color |circle: draw a circle using current line width and color |circleprecision: set number of line segments making up a circle | |drawchar: draw text at the current position |drawstr: draw text at the current position | |linewidth: set line width for lines drawn in pixel image |color: set current color for lines drawn in pixel image |textsize: set text size in world units |ycentertext: set centering mode for drawstr(3f)/drawc(3f) in Y direction |xcentertext: set centering mode for drawstr(3f)/drawc(3f) in X direction |centertext: set centering mode for drawstr(3f)/drawc(3f) |textang: set angle in degrees to draw text at using drawstr(3f) | |mapcolor: set a color index using RGB values | |strlength: length of string using current font size |getviewport: return viewport in screen pixel coordinates |getdisplaysize: Returns the width and height of the device in pixels |state: print graphics state of M_pixel graphics module |getgp2: get current graphics position | |viewport: Specify which part of the screen to draw in. |ortho2: define area of virtual world coordinates to map to viewport |ortho2_biggest: given window size, set to largest accommodating viewport | |print_ppm: print pixel array as a P3 PPM file |print_ascii: print pixel array as an ASCII block of text | |clear: set background color all to specified color index | |vexit: exit pixel array drawing module | | | | #-------------------------------------------------------------------------# | help | | display this information | | | | this information | | quit|. | | exit program | #-------------------------------------------------------------------------# | anything_else | execute as system command | #-------------------------------------------------------------------------#It can be confusing if you make variables that are command names. An expression on the command line is evaluated and then the program exits.
EXAMPLE
Sample input file
today year-month-day hour:minute:second today set A=10 set b=20 if lt(A,b) echo A is less than B set C=sin(sqrt(2)) elseif eq(b,10) echo did not expect to get here else echo did not expect to get here either endif#################### calculator mode set x=A+b+C y=cos(A)/sin(b)+C z=max(A,b,C) $A="This is a string" . ####################
set dump # display available functions set funcs
set $str($A," function call") ######################## set up PIXEL display prefsize 500 500 vinit ortho2 -100 100 -100 100 ######################## draw some shapes color 6 makepoly rect -100 -100 0 0 closepoly
color 3 makepoly rect -100 100 0 0 closepoly
makepoly color 4 rect 0 0 100 100 closepoly
makepoly color 5 rect 0 0 100 -100 closepoly
color 2 linewidth 400 circleprecision 128 circle 0 0 100 circle 0 0 50 ######################## Draw X color 1 linewidth 500 set x=100 move2 0-x 0-x draw2 x x move2 0-x x draw2 x 0-x ######################## draw some text linewidth 90 color 7 textsize 10 10 centertext .T. move2 0 0 textang 45 drawstr Hello World! centertext .F. ######################## print_ppm sample.ppm clear vexit ######################## # assuming you have imagemagick installed display sample.ppm ######################## quit
AUTHOR
John S. Urban
LICENSE
Public Domain
| Nemo Release 3.1 | shell (1) | February 23, 2025 |
