trc: add subscript sequences (Erik Quanstrom) - plan9port - [fork] Plan 9 from user space
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---
(DIR) commit 94e1f2a4388f674331b2a2f988fb815133d2ab6b
(DIR) parent 78a779a3834cf39d7c0bcd93a15824b29df947a3
(HTM) Author: Russ Cox <rsc@swtch.com>
Date: Sun, 20 Jul 2008 04:15:41 -0400
rc: add subscript sequences (Erik Quanstrom)
Diffstat:
M man/man1/rc.1 | 5 +++++
M src/cmd/rc/exec.c | 40 +++++++++++++++++++++++++++----
2 files changed, 40 insertions(+), 5 deletions(-)
---
(DIR) diff --git a/man/man1/rc.1 b/man/man1/rc.1
t@@ -208,6 +208,11 @@ If
is followed by a parenthesized list of subscripts, the
value substituted is a list composed of the requested elements (origin 1).
The parenthesis must follow the variable name with no spaces.
+Subscripts can also take the form
+.IB m - n
+or
+.IB m -
+to indicate a sequence of elements.
Assignments to variables are described below.
.HP
.BI $# argument
(DIR) diff --git a/src/cmd/rc/exec.c b/src/cmd/rc/exec.c
t@@ -686,21 +686,51 @@ Xqdol(void)
}
word*
+copynwords(word *a, word *tail, int n)
+{
+ word *v, **end;
+
+ v = 0;
+ end = &v;
+ while(n-- > 0){
+ *end = newword(a->word, 0);
+ end = &(*end)->next;
+ a = a->next;
+ }
+ *end = tail;
+ return v;
+}
+
+word*
subwords(word *val, int len, word *sub, word *a)
{
- int n;
+ int n, m;
char *s;
if(!sub)
return a;
a = subwords(val, len, sub->next, a);
s = sub->word;
deglob(s);
+ m = 0;
n = 0;
- while('0'<=*s && *s<='9') n = n*10+ *s++ -'0';
- if(n<1 || len<n)
+ while('0'<=*s && *s<='9')
+ n = n*10+ *s++ -'0';
+ if(*s == '-'){
+ if(*++s == 0)
+ m = len - n;
+ else{
+ while('0'<=*s && *s<='9')
+ m = m*10+ *s++ -'0';
+ m -= n;
+ }
+ }
+ if(n<1 || n>len || m<0)
return a;
- for(;n!=1;--n) val = val->next;
- return newword(val->word, a);
+ if(n+m>len)
+ m = len-n;
+ while(--n > 0)
+ val = val->next;
+ return copynwords(val, a, m+1);
}
void