cmds.projects.lib.templates.tmpl_render(): RenderValues

tmpl_render()'s "values" argument currently understands
dict[str,str|list[str]]. Enhance that to understand the broader
RenderValues type, which also includes Iterable[tuple[str, str]], as
produced by argparse.add_argument(action='append').

This commit also adds proper type-checking for the values argument.
Before, its type had gone unchecked entirely.

Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/cmds/projects/lib/templates.py

@@ -1,7 +1,79 @@
 import textwrap
+from typing import Iterable, TypeAlias, TypeGuard
 
-def format_lines(
-    template: str, values: dict[str, str], li_quote: bool, li_delimiter: str
+TupleList: TypeAlias = Iterable[tuple[str, str]]
+ListDict: TypeAlias = dict[str, list[str]]
+StrDict: TypeAlias = dict[str, str]
+RenderValues: TypeAlias = ListDict | StrDict | TupleList
+
+def is_str_dict(values: RenderValues) -> TypeGuard[StrDict]:
+    if not isinstance(values, dict):
+        return False
+    for key, val in values.items():
+        if not isinstance(key, str):
+            return False
+        if not isinstance(val, str):
+            return False
+    return True
+
+def is_list_dict(values: RenderValues) -> TypeGuard[ListDict]:
+    if not isinstance(values, dict):
+        return False
+    for key, val in values.items():
+        if not isinstance(key, str):
+            return False
+        if isinstance(val, str):
+            continue
+        if not isinstance(val, list):
+            return False
+        for entry in val:
+            if not isinstance(entry, str):
+                return False
+    return True
+
+def is_tuple_list(values: RenderValues) -> TypeGuard[TupleList]:
+    if not isinstance(values, list):
+        return False
+    for item in values:
+        if not isinstance(item, tuple):
+            return False
+        if not len(item) == 2:
+            return False
+        if not isinstance(item[0], str):
+            return False
+        if not isinstance(item[1], str):
+            return False
+    return True
+
+def render_values_to_list_dict(values: RenderValues) -> ListDict:
+
+    def __tuple_list_to_dict(src: TupleList) -> ListDict:
+        ret: ListDict = {}
+        for key, val in src:
+            entry = ret.setdefault(key, [])
+            entry.append(val)
+        return ret
+
+    if is_list_dict(values):
+        return values
+    if is_tuple_list(values):
+        return __tuple_list_to_dict(values)
+    raise Exception('Unsupported template value layout')
+
+def merge_values(*values: RenderValues) -> ListDict:
+    ret: ListDict = {}
+    for rhs in values:
+        rhs_dict = render_values_to_list_dict(rhs)
+        for key, val in rhs_dict.items():
+            entry = ret.setdefault(key, [])
+            if isinstance(val, list):
+                entry += val
+            else:
+                entry.append(val)
+    return ret
+
+def format_list_dict(
+    template: str, values: ListDict | dict[str, str], li_quote: bool, li_delimiter: str
 ) -> str:
 
     def __format_value(val):
@@ -9,15 +81,18 @@ def format_lines(
             return str(val)
         return f'"{val}"'
 
+    fmt_dict: dict[str, str] = {}
     for key, value in values.items():
         if isinstance(value, (list, tuple)):
-            values[key] = li_delimiter.join(map(__format_value, value))
+            fmt_dict[key] = li_delimiter.join(map(__format_value, value))
+        elif isinstance(value, str):
+            fmt_dict[key] = value
 
-    ret = []
+    ret: list[str] = []
     parts = template.splitlines(keepends = True)
 
     for line in parts:
-        for key, value in values.items():
+        for key, value in fmt_dict.items():
             marker = '{' + key + '}'
             if marker in line:
                 indent = line[:line.index(marker)]
@@ -27,6 +102,11 @@ def format_lines(
 
     return ''.join(ret)
 
+def format_lines(
+    template: str, values: list[RenderValues], li_quote: bool, li_delimiter: str
+) -> str:
+    return format_list_dict(template, merge_values(*values), li_quote, li_delimiter)
+
 _templates = {
     'pkg-config':
     """\
@@ -66,7 +146,7 @@ _templates = {
 
 def tmpl_render(
     template_name: str,
-    values,
+    values: list[RenderValues],
     li_quote = False,
     li_delimiter = '\n',
     search_path: list[str] = []