regex - sed to replace comma outside parentheses -

i have partial sql string.

select id,to_char(ts2date(created_t),'dd-mm-yyyy'),name,segment_code sometable 

using sed, tried replace comma reside outside outmost parentheses string char '~'.

the desired result be:-

select id~to_char(ts2date(created_t),'dd-mm-yyyy')~name~segment_code sometable 

here tried:-

sed ' :a s/[,]\(.*(\)/~\1/g s/\().*\)[,]/\1~/g ta 

but result become:-

select id~to_char(ts2date(created_t)~'dd-mm-yyyy')~name~segment_code sometable 

how can ignore comma inside outmost parentheses?

tq answer .. :)

it's not possible reach such goal pure sed regex. correct/incorrect bracketing , depth cannot recognized regular automatas (and therefore cannot recognized regular expressions).

if want reach "regex", might want use perl , look-ahead/look-behind features. or write simple loop checks bracketing.