I wonder if I'm the only one bothered by semicolon's assertion of strictly
i>j.
Generally, empty words can be used as markers to impose some additional
regularity on the output, to make it easier to process later.
An obvious example would be parsing a csv file with 3 fields per record
where any can be empty:
,,
,1st field, Is empty
Full record, 3, "Hello, world"
It is natural to parse it into empty strings where appropriate, but i>j
gets into a way.
Letting i>:j in and adding 3( for the sake of completeness) new opcodes
like below seems to be increasing SM's usefulness considerably in mostly
backwards compatible way. What do others think?
8 j=.i+1
9 j=.i+1 [ ew(i,j,r,c)
10 j=.i+1 [ ev(i,j,r,c)
NB. Rows: 0: Waiting for terminating comma, 1: Inside of quotes
NB. Columns: 0: comma, 1: double quotes, 2: other
<"1 (2 3 2$ 0 9 1 1 0 0 1 0 0 0 1 0)
+---+---+---+
|0 9|1 1|0 0|
+---+---+---+
|1 0|0 0|1 0|
+---+---+---+
csv =: (0;(2 3 2$ 0 9 1 1 0 0 1 0 0 0 1 0 );(',';'"');0 0 0 _1 ) &
;:
csv ',,'
++++
||||
++++
csv ',1st field, Is empty'
++---------+---------+
||1st field| Is empty|
++---------+---------+
csv 'Full record, 3, "Hello, world"'
+-----------+--+--------------+
|Full record| 3|"Hello, world"|
+-----------+--+--------------+
====
dlab:~/Sources/jsource-master/jsrc$ diff w.c w.c.orig
251c251
< #define CHKJ(j) ASSERT(BETWEENC((j),0,i),EVINDEX);
---
> #define CHKJ(j) ASSERT(BETWEENO((j),0,i),EVINDEX);
272,274d271
< case 8: j=i+1; break;
\
< case 9: if(0<=vi){EMIT(T,vj,vi,vr,vc); vi=vr=-1;}
EMIT(T,j,i,r,c); j=i+1; break; \
< case 10: if(r!=vr){if(0<=vi)EMIT(T,vj,vi,vr,vc); vj=j; vr=r;
vc=c;} vi=i; j=i+1; break; \
339c336
< v=sv; DQ(p*q, k=*v++; e=*v++;
ASSERT((UI)k<(UI)p&&(UI)e<=(UI)10,EVINDEX););
---
> v=sv; DQ(p*q, k=*v++; e=*v++;
ASSERT((UI)k<(UI)p&&(UI)e<=(UI)7,EVINDEX););
346c343
< if(2<=n){ijrd[1]=j=*v++; ASSERT(BETWEENC(j, -1, i),EVINDEX);}
---
> if(2<=n){ijrd[1]=j=*v++; ASSERT(BETWEENO(j, -1, i),EVINDEX);}
regards,
Danil
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