aboutsummaryrefslogtreecommitdiff
path: root/unix/boot/spp/rpp/rpprat/caslab.r
blob: 12d3c0da34263c98f761a87bb9a6512d385f1d1a (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
include  defs

# caslab - get one case label

integer function caslab (n, t)

integer n, t
character tok(MAXTOK)
integer i, s, lev
integer gnbtok, ctoi

	t = gnbtok (tok, MAXTOK)
	while (t == NEWLINE)
	    t = gnbtok (tok, MAXTOK)

	if (t == EOF)
	    return (t)

	for (lev=0;  t == LPAREN;  t = gnbtok (tok, MAXTOK))
	    lev = lev + 1

	if (t == MINUS)
	    s = -1
	else
	    s = +1
	if (t == MINUS | t == PLUS)
	    t = gnbtok (tok, MAXTOK)

	if (t != DIGIT)
	    goto 99
	else {
	    i = 1
	    n = s * ctoi (tok, i)
	}

	for (t=gnbtok(tok,MAXTOK);  t == RPAREN;  t=gnbtok(tok,MAXTOK))
	    lev = lev - 1
	if (lev != 0)
	    goto 99

	while (t == NEWLINE)
	    t = gnbtok (tok, MAXTOK)

	return

 99	call synerr ("Invalid case label.")
	n = 0
end