2 files changed, 28 insertions, 1 deletions
diff --git a/src/smp/builtins.py b/src/smp/builtins.py
index c1d67ce..3ff15c6 100644
--- a/src/smp/builtins.py
+++ b/src/smp/builtins.py
@@ -20,7 +20,7 @@ def smp_builtin_define(macro_processor, macro_name, macro_value=None):
 
 def smp_builtin_undefine(macro_processor, macro_name):
     if macro_name in macro_processor.macros:
-        del macro_processor[macro_name]
+        del macro_processor.macros[macro_name]
     return ""
 
 
diff --git a/src/smp/macro_processor.py b/src/smp/macro_processor.py
index bda6c6f..68fd726 100644
--- a/src/smp/macro_processor.py
+++ b/src/smp/macro_processor.py
@@ -31,6 +31,30 @@ def macro_name_clean(macro_name: str) -> str:
     return macro_name
 
 
+def seek(input: str, start: int, target: str) -> int | None:
+    """Seek for a value in a string, consider using startswith instead"""
+    from warnings import warn
+
+    warn(
+        "seek should be considered replaced with str.startswith",
+        DeprecationWarning,
+        stacklevel=2,
+    )
+    input_end = len(input)
+    target_end = len(target)
+
+    if input_end < start + target_end:
+        return None
+
+    i = 0
+    while i < len(target):
+        if input[start + i] != target[i]:
+            return None
+        i += 1
+
+    return start + target_end
+
+
 class MacroProcessor:
     """All currently defined macros in this MacroProcessor"""
 
@@ -46,6 +70,9 @@ class MacroProcessor:
 
     special_macros: dict[str, tuple[Any, Any]]
 
+    start_quote: str = '%"'
+    end_quote: str = '"%'
+
     def __init__(self, prefix=""):
         self.macros = dict()
         self.macro_invocations = list()