1 files changed, 45 insertions, 0 deletions
diff --git a/tools/cru-py/crupest/template2.py b/tools/cru-py/crupest/template2.py
new file mode 100644
index 0000000..ae096df
--- /dev/null
+++ b/tools/cru-py/crupest/template2.py
@@ -0,0 +1,45 @@
+import os.path
+import re
+
+_template_filename_suffix = ".template"
+_template_var_regex = r"\$([-_a-zA-Z0-9]+)"
+_template_var_brace_regex = r"\$\{\s*([-_a-zA-Z0-9]+?)\s*\}"
+
+
+class Template2:
+
+    @staticmethod
+    def from_file(template_path: str) -> "Template2":
+        if not template_path.endswith(_template_filename_suffix):
+            raise Exception(
+                "Template file must have a name ending with .template.")
+        template_name = os.path.basename(
+            template_path)[:-len(_template_filename_suffix)]
+        with open(template_path, "r") as f:
+            template = f.read()
+        return Template2(template_name, template, template_path=template_path)
+
+    def __init__(self, template_name: str, template: str, *, template_path: str | None = None) -> None:
+        self.template_name = template_name
+        self.template = template
+        self.template_path = template_path
+        self.var_set = set()
+        for match in re.finditer(_template_var_regex, self.template):
+            self.var_set.add(match.group(1))
+        for match in re.finditer(_template_var_brace_regex, self.template):
+            self.var_set.add(match.group(1))
+
+    def partial_render(self, vars: dict[str, str]) -> "Template2":
+        t = self.render(vars)
+        return Template2(self.template_name, t, template_path=self.template_path)
+
+    def render(self, vars: dict[str, str]) -> str:
+        for name in vars.keys():
+            if name not in self.var_set:
+                raise ValueError(f"Invalid var name {name}.")
+
+        text = self.template
+        for name, value in vars.items():
+            text = text.replace("$" + name, value)
+            text = re.sub(r"\$\{\s*" + name + r"\s*\}", value, text)
+        return text