string: add substring method

This method aims to offer a simple way to 'substring'
an existing string with start and end values.

2 files changed, 23 insertions, 0 deletions

diff --git a/docs/markdown/Reference-manual.md b/docs/markdown/Reference-manual.md
index 966d408..080fe3e 100644
--- a/docs/markdown/Reference-manual.md
+++ b/docs/markdown/Reference-manual.md
@@ -1977,6 +1977,9 @@ are immutable, all operations return their results as a new string.
 - `startswith(string)`: returns true if string starts with the string
   specified as the argument
 
+- `substring(start,end)` *(since 0.56.0)*: returns a substring specified from start to end.
+  Both `start` and `end` arguments are optional, so, for example, `'foobar'.substring()` will return `'foobar'`.
+
 - `strip()`: removes whitespace at the beginning and end of the string.
   *(since 0.43.0)* Optionally can take one positional string argument,
   and all characters in that string will be stripped.
diff --git a/docs/markdown/Syntax.md b/docs/markdown/Syntax.md
index 7cb39e9..bbe3dbb 100644
--- a/docs/markdown/Syntax.md
+++ b/docs/markdown/Syntax.md
@@ -220,6 +220,26 @@ is_x86 = target.startswith('x86') # boolean value 'true'
 is_bsd = target.to_lower().endswith('bsd') # boolean value 'true'
 ```
 
+#### .substring()
+
+Since 0.56.0, you can extract a substring from a string.
+
+```meson
+# Similar to the Python str[start:end] syntax
+target = 'x86_FreeBSD'
+platform = target.substring(0, 3) # prefix string value 'x86'
+system = target.substring(4) # suffix string value 'FreeBSD'
+```
+
+The method accepts negative values where negative `start` is relative to the end of
+string `len(string) - start` as well as negative `end`.
+
+```meson
+string = 'foobar'
+target.substring(-5, -3) # => 'oo'
+target.substring(1, -1) # => 'ooba'
+```
+
 #### .split(), .join()
 
 ```meson