libreDSSP Core Words

libreDSSP provides a set of built-in "core" words. These words cannot be removed or redefined once libreDSSP has been built. All other libreDSSP programs consist of concatenations of these core words.

The table below summarizes core words that are meant to be used in libreDSSP code and/or the interactive prompt. Currently there are some other core words "under the hood" that are not meant to be used explicitly. Those are not documented here, and a future version of libreDSSP will make them inaccessible anyway.

As work on libreDSSP progresses, the table will get longer. Refer to the list of non-working features on our GitHub repository.

The order is mostly alphabetical with some minor variances for the purpose of grouping. I will probably introduce organized sections later.

Obviously, the table isn't done yet. I think has all of the rows at least.

Core word	Description	Example
+	Add
-	Subtract
*	Multiply
/	Divide
<	Less than
>	Greater than
=	Equal
.	Show top of stack
..	Show entire stack
!	Assign top of stack to an existing variable
?$	List available subdictionaries
0	Push 0
1	Push 1
2	Push 2
4	Push 4
8	Push 8
1+	Add 1 to top of stack
1-	Subtract 1 from top of stack
2+	Add 2 to top of stack
2-	Subtract 2 from top of stack
3+	Add 3 to top of stack
3-	Subtract 3 from top of stack
4+	Add 4 to top of stack
4-	Subtract 4 from top of stack
ABS	Take absolute value of top of stack
B10	Set mode to Base 10 arithmetic (placeholder)
BR	Multi-clause branch
BR+	Branch on positive
BR0	Branch on zero
BR-	Branch on negative
BRS	Three-way branch on sign
BYE	Exit libreDSSP
C	Duplicate top of stack
C2	Copy cell from depth 2 to top of stack
C3	Copy cell from depth 3 to top of stack
C4	Copy cell from depth 4 to top of stack
CT	Consume top stack cell and copy the cell from given depth to top of stack
CR	Print a newline
D	Drop the top cell from the stack
DEEP	Push the stack depth to the stack
DEL	Delete a named object (globally patches all refs to safe errors)
DO	Loop a word a given number of times
DS	Drop the entire stack contents
E2	Exchange the top stack cell with the cell below it
E3	Exchange the top stack cell with the cell at depth 3
E4	Exchange the top stack cell with the cell at depth 4
ET	Consume top stack cell and exchange new top cell with the cell at given depth
EX	Exit from the current innermost loop
EX+	Consume the top stack cell and if it is positive, exit from the current innermost loop
EX0	Consume the top stack cell and if it is zero, exit from the current innermost loop
EX-	Consume the top stack cell and if it is positive, exit from the current innermost loop
EXT	Consume the top stack cell and exit from that many layers of ongoing loops
GROW	Select a subdictionary for expansion
IF+	Consume top stack cell; If the value is positive, execute the following word; Otherwise skip it
IF0	Consume top stack cell; If the value is zero, execute the following word; Otherwise skip it
IF-	Consume top stack cell; If the value is negative, execute the following word; Otherwise skip it
NEG	Negate the cell at top of stack
NOP	Do nothing (no-op)
RP	Repeat the following word until a loop exit is triggered
SEE	Print the current definitions bound to a name (in all subdictionaries)
SHUT	Disable lookup access to a given subictionary
SP	Print a space
TIN	Terminal Input Number
TON	Terminal Output Number
TOS	Terminal Output String
UNDEF	List undefined words
USE	Enable lookup access to a given subdictionary
VAR	Declare a new variable (init to 0)
VARS	List all user-defined variables
WORDS	List all user-defined words