[gforth] / gforth / quotations.fs

gforth: gforth/quotations.fs

1 :	pazsan	1.1	\ anonymous definitions in a definition
2 :
3 :			:noname false :noname ;
4 :			:noname locals-wordlist last @ lastcfa @
5 :	pazsan	1.2	postpone AHEAD
6 :	anton	1.3	locals-list @ locals-list off
7 :			postpone SCOPE
8 :			true :noname ;
9 :	pazsan	1.2	interpret/compile: [: ( -- quotation-sys )
10 :			\G Starts a quotation
11 :	pazsan	1.1
12 :	pazsan	1.2	: ;] ( compile-time: quotation-sys -- ; run-time: -- xt )
13 :			\g ends a quotation
14 :	pazsan	1.1	POSTPONE ; >r IF
15 :	pazsan	1.2	] postpone ENDSCOPE
16 :	anton	1.3	locals-list !
17 :	pazsan	1.2	postpone THEN
18 :	pazsan	1.1	lastcfa ! last ! to locals-wordlist
19 :	pazsan	1.2	r> postpone ALiteral
20 :	pazsan	1.1	ELSE r> THEN ( xt ) ; immediate
21 :
22 :	pazsan	1.2	0 [IF] \ tests
23 :	pazsan	1.1	: if-else ( ... f xt1 xt2 -- ... )
24 :			\ Postscript-style if-else
25 :			rot IF
26 :			drop
27 :			ELSE
28 :			nip
29 :			THEN
30 :			execute ;
31 :
32 :			: test ( f -- )
33 :			[: ." true" ;]
34 :			[: ." false" ;]
35 :			if-else ;
36 :
37 :			1 test cr \ writes "true"
38 :			0 test cr \ writes "false"
39 :	pazsan	1.2
40 :			\ locals within quotations
41 :
42 :			: foo { a b } a b
43 :			[: { x y } x y + ;] execute . a . b . ;
44 :			2 3 foo
45 :			[THEN]