string-scan

hyTags

string-scan

Matches a substring or pattern from the start of the string. Useful for parsers and tokenizers. Either substring or pattern must be provided, but not both.

self

String

String to scan from the beginning

substring

String?

Literal substring to match at the start

pattern

String?

Regular expression pattern to match at the start

return

string

The matched portion of the string, or nil if no match

Test Case:Scan substring from start

<div></div>

<string-new value="hello world">
<string-scan substring="hello">
<assert-equal value="hello" type="string">

Test Case:Scan pattern from start

<div></div>

<string-new value="123abc">
<string-scan pattern="[0-9]+">
<assert-equal value="123" type="string">

Test Case:Scan returns nil when no match at start

<div></div>

<string-new value="abc123">
<string-scan pattern="[0-9]+">
<value-is-nil>
<assert-true>

Test Case:Scan special characters

<div></div>

<string-new value="
	&quot;hello">
<string-scan pattern="[\n\t&quot;]+">
<assert-equal value="
	&quot;" type="string">

Test succeeded

Test failed