| Directive | Sample Usage | Description |
| !alias | !alias c clear (makes !c mean !clear) |
Associate one Directive with another |
| !allocate | !allocate !allocate 10000000 |
Display Setting or Increase ISETLW Workspace Allocated Memory. Cannot exceed upper bound set by !memory. ISETL(W) will automatically increase allocated memory as needed, but you can pre-allocate a large amount if desired. |
| !clear | > f := func(x,y,z); >> blah := x; >> stuff := blah*blah*y; >> !clear !clear complete > |
Throw away all input back to the last single prompt. Sometimes given a syntax error ISETL will automatically clear. Sometimes when double-prompted and confused a user will manually !clear to start fresh. |
| !code | !code !code on !code off |
Display Setting or Toggle on/off. Display pseudo-assembly listing of input |
| !credits | !credits | Display Credits (Use Help | About ISETLW) |
| !echo | !echo !echo on !echo off |
Display Setting or Toggle on/off. Redisplay input line when executing it. Useful when trying to find a syntax error in an !include file |
| !fast | Unsupported in ISETLW | Run ISETLW at full speed (see !slow) |
| !gc | !gc !gc on !gc off |
Display Setting or Toggle on/off. Display memory garbage collection statistics |
| !ids | !ids | Display all Defined Identifiers |
| !include | !include FileName.stl !include H:\data\FileName.stl |
Execute a File of ISETL Commmands |
| !lock | !lock x !lock x y |
Prevent Assignment or Reassignment to an Identifier (See !unlock) |
| !locked | !locked | Display all Locked Identifiers |
| !memory | !memory !memory 40000000 |
Display Setting or Increase ISETLW Workspace Memory Upper Bound |
| !oms | !oms | Display all Used, but Undefined Identifiers |
| !pp | > !pp f f := func(x); return x*x; end; > |
Display the source for a Function or Procedure |
| !quit | !quit | Exit ISETLW (Same as File | Exit) |
| !rational | !rational !rational on !rational off |
Display Setting or Toggle on/off. Use Fractions versus Rational Numbers |
| !record | !record FileName.stl !record |
Record Input to a File. !record with no parameter means turn off recording and close the file. |
| !setrandom | !setrandom !setrandom on !setrandom off |
Display Setting or Toggle on/off. Display Sets with or without an ordering. |
| !slow | Unsupported in ISETLW | Run ISETL one function call at a time (see !fast) |
| !source | Unsupported in ISETLW. | Save Source for debugging with !slow, !stack, etc. |
| !stack | !stack !stack on !stack off |
Display Setting or Toggle on/off. Show function calls left on stack after an error. |
| !system | Unsupported in ISETLW | Create a DOS shell and run a DOS command (Unsupported in ISETLW, use File | Dos shell) |
| !trace | !trace !trace on !trace off |
Display Setting or Toggle on/off. Show Execution of ISETL statements in pseudo-assembly. Really intended for debugging ISETL itself. |
| !unlock | !unlock x !unlock x y |
Allow Assignment or Reassignment to an Identifier (See !lock) |
| !unwatch | !unwatch x !unwatch x y |
Stop Watching an Identifier or a List of Identifiers. (See !watch) |
| !verbose | !verbose !verbose on !verbose off |
Display Setting or Toggle on/off. Amount of information after certain errors. |
| !version | !version | Displays ISETL Version number (in ISETLW use Help | About ISETLW) |
| !watch | !watch x !watch x y |
Display All Changes (or Evaluations if it's a function) of an Identifier or a List of Identifiers. (See !unwatch) |