javascript - Using Regex to extract line numbers of GOTOs/GOSUBs -


i'm trying extract gotos/gosubs line numbers basic code. intend use nodejs manage matches (so it's js-flavoured regex).

i'm doing tests using regex101.com (see here https://regex101.com/r/sazuue/2 ) , i'm pretty close want:

  • extract goto ### ["goto", " ", "###"]
  • extract gosub ### ["gosub", " ", "###"]
  • extract if (cond) ### ["then", " ", "###"]
  • extract on err goto #, ##, ### ["goto", " ", "#", ", ", "##", ", ", "###"]
  • same above on err gosub
  • deal fact spaces between goto, gosub, then , , optional or can multiple , in cases return exact number of spaces indicated.

so far have come following regex:

/(goto|gosub|then)(\s*)(\d+)(?:(\s*,\s*)(\d+))*/ig

testing on:

100 on err goto 10000, 30, 200, 10,800: gosub 20: if 10: goto30: goto 50

all matching groups ok except on err goto returns first , last numbers (10000 & 800) , not others.

what missing ? :)

there no way have arbitrary number of captures regex, , there no way access multiple captures within single group js regexp not store capture value stack each group (the subsequent capture re-writes existing one, , thus, last capture stored per group).

capture streak of comma-separated numbers , split them separately. e.g. make end of pattern ((?:\s*,\s*\d+)*) (to match 0+ sequences of , enclosed 0+ whitespaces followed 1+ digits) , then, upon match, split /\s*,\s*/ , filter.

see js demo:

var rx = /\b(go(?:to|sub)|then)(\s*)(\d+)((?:\s*,\s*\d+)*)/gi;  var str = "100 on err goto 10000, 30,   200, 10,800: gosub 20: if 10: goto30: goto  50";  var m;  while ((m = rx.exec(str)) !== null) {     console.log( [m[1], m[2], m[3], m[4].split(/\s*,\s*/).filter(boolean)] );  }


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