Author: anon.hui

Description:
{{ #substr: str | pos | len }} == {{ #mid: str | pos | len }}
{{ #substr: abcdef | 1 | 3 }} --> bcd
{{ #substr: abcdef | 1 }} --> bcdef
{{ #substr: abcdef | 0 | 3 }} --> abc

• The "pos" and "len" can also be negative, and have the same behavior as php's substr()

{{ #head: str | len }} == {{ #left | len }} == {{ #substr: str | 0 | len }}
{{ #tail: str | len }} == {{ #right | len }} == {{ #substr: str | -len }}

If you need patch, I'm going to implement it.

Version: unspecified
Severity: enhancement