Forth implementations and tools

Sources
Gforth

Sources

Gforth Manual — 5.24 Programming Tools

Gforth

Install

$ brew install gforth

Use interactively

$ gforth
Gforth 0.7.3, Copyright (C) 1995-2008 Free Software Foundation, Inc.
Gforth comes with ABSOLUTELY NO WARRANTY; for details type `license'
Type `bye' to exit
2 2 + . 4  ok
bye

Run file from command line

$ gforth basics.forth

Interpreter and system state

page to clear display
cold to restart Forth environment
bye to exit Forth environment to OS

Print debugging

The word ~~ will print the source line and stack contents at that point.

: f ( -- n ) clearstack 1 ~~ 2 ~~ ;
f

/Users/blennon/temp/temp.forth:1:<1> 1
/Users/blennon/temp/temp.forth:1:<2> 1 2

Stepping through code

Gforth includes a single-step debugger. You must invoke the gforth-itc engine:

$ gforth-itc
Gforth 0.7.3, Copyright (C) 1995-2008 Free Software Foundation, Inc.
Gforth comes with ABSOLUTELY NO WARRANTY; for details type `license'
Type `bye' to exit
: add1 1 + ;  ok
2 dbg add1
: add1
Scanning code...

Nesting debugger ready!
[ 1 ] 00002
10997E270 10989C560 1              -> [ 2 ] 00002 00001
10997E280 10989C568 +              -> [ 1 ] 00003
10997E288 10989C428 ;              ->  ok
bye

break: in source code will invoke the debugger. Can only be used in compile-time (colon) definitions.

: f ( n -- n ) 1 2 + 3 break: * 4 / ;
0 f .
bye

$ gforth-itc ~/temp/temp.forth

Scanning code...
<4447085322> <0>
Nesting debugger ready!
[ 3 ] 00000 00003 00003
1092242C8 1091405B8 *              -> [ 2 ] 00000 00009
1092242D0 109140560 4              -> [ 3 ] 00000 00009 00004
1092242E0 1091405C0 /              -> [ 2 ] 00000 00002
1092242E8 109140428 ;              -> 2

break" string" will include a label.

: f ( n -- n ) 1 2 + 3 break" multiplication" * 4 / ;
0 f .
bye

$ gforth-itc ~/temp/temp.forth

BREAK AT: multiplication

Scanning code...
<4335170314> <0>
Nesting debugger ready!
[ 3 ] 00000 00003 00003
102768308 1026855B8 *              -> [ 2 ] 00000 00009
102768310 102685560 4              -> [ 3 ] 00000 00009 00004
102768320 1026855C0 /              -> [ 2 ] 00000 00002
102768328 102685428 ;              -> 2

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