s4_ltrim(string)

Removes leading whitespace from string:

⇐ {s4_ltrim([
⇐     String])}

⇒ {String}

Non-leading (i. e. trailing and inner) whitespace remains intact:

⇐ {s4_ltrim([S  t  r
⇐     ing
⇐     ])}

⇒ {S  t  r
⇒     ing
⇒     }

Result is quoted:

⇐ {s4_ltrim([m4_toupper([String])])}

⇒ {m4_toupper([String])}

(Note: m4_toupper macro is not expanded.)