Gri Commands
1: Introduction
2: Simple example
3: Fancy example
4: Running Gri
5: Programming Gri
6: General Issues
7: X-Y Plots
8: Contour Plots
9: Image Plots
10: Examples
11: Handling Data
12: Gri Commands
13: Gri Extras
14: Evolution of Gri
15: Installing Gri
16: Gri Bugs
17: System Tools
18: Acknowledgments
19: License
20: Newsgroup
21: Concept Index
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12.1: Overview of Gri Commands
The first word of a command hints at the meaning, but apart from that,
here is a rough guide:
- File manipulation
Commands are `
open ', `close ', `skip ', `read ', and
`rewind '.
- Control parameters
Various `
set ' commands control values of parameters, like size of plot,
linewidth, font, etc.
- Drawing things
Various `
draw ' commands let you draw data, axes, etc.
- Interaction with user
The `
query ' command gets instructions from the user. The
`show ' command displays messages to user.
- Control program flow
The `
if ' statement controls optional execution of commands
see If Statements. The `while ' statement allows loops.
- Directory control
The `
pwd ', `cd ' and `ls ' commands do the usual unix
things.
- Interaction with operating system
The `
system ' command passes instructions to the operating system;
the output may be saved into a synonym by using
`\syn = system ... '. The `get env ' command determines the value of any
unix environment variables the system has defined. For more discussion
see Operating System.
- Statistics
Some very limited capabilities exist; for example, `
regress ' does
linear regression.
- Mathematics
Simple mathematical manipulation of column, grid, and image data is
provided. Also, wherever Gri expects a number, it will accept a
reverse-polish expression; for example, `
set x size 10 ' could also
be written `set x size {rpn 20 2 /} '. For details
see Mathematics.
The data types in Gri are columns, grids, images, scalar variables
and ``synonyms'' that is, strings see Synonyms,
see Variables.
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