Add support for basic format strings

1 files changed, 14 insertions, 0 deletions

diff --git a/mesonbuild/interpreterbase.py b/mesonbuild/interpreterbase.py
index 026eaf2..d486b89 100644
--- a/mesonbuild/interpreterbase.py
+++ b/mesonbuild/interpreterbase.py
@@ -708,6 +708,8 @@ class InterpreterBase:
             return self.evaluate_indexing(cur)
         elif isinstance(cur, mparser.TernaryNode):
             return self.evaluate_ternary(cur)
+        elif isinstance(cur, mparser.FormatStringNode):
+            return self.evaluate_fstring(cur)
         elif isinstance(cur, mparser.ContinueNode):
             raise ContinueRequest()
         elif isinstance(cur, mparser.BreakNode):
@@ -926,6 +928,18 @@ The result of this is undefined and will become a hard error in a future Meson r
         else:
             return self.evaluate_statement(node.falseblock)
 
+    def evaluate_fstring(self, node: mparser.FormatStringNode) -> TYPE_var:
+        assert(isinstance(node, mparser.FormatStringNode))
+
+        def replace(match: T.Match[str]) -> str:
+            var = str(match.group(1))
+            try:
+                return str(self.variables[var])
+            except KeyError:
+                raise mesonlib.MesonException(f'Identifier "{var}" does not name a variable.')
+
+        return re.sub(r'{([_a-zA-Z][_0-9a-zA-Z]*)}', replace, node.value)
+
     def evaluate_foreach(self, node: mparser.ForeachClauseNode) -> None:
         assert(isinstance(node, mparser.ForeachClauseNode))
         items = self.evaluate_statement(node.items)