Make text-view template substitution single-pass

docs/output-emit-text-views.md

@@ -41,7 +41,7 @@ Missing `for_each` values, `null`, and empty strings render no lines. Present no
 
 ## Placeholders And Filters
 
-Templates replace `{path}` placeholders with scalar values. Empty `{}` and `{.}` refer to the current item. `root.` paths resolve against the root result payload.
+Templates replace `{path}` placeholders with scalar values in a single pass over the original template. Placeholder-looking text introduced by a replacement is emitted literally and is not expanded again. Empty `{}` and `{.}` refer to the current item. `root.` paths resolve against the root result payload.
 
 Direct placeholders accept JSON scalars only. Arrays and objects must use the explicit `{"json": "path"}` line form. Missing values and null render as an empty string.
 

src/command_generation/primitive_executor.py

@@ -3,6 +3,7 @@
 import importlib
 import json
 import math
+import re
 import tomllib
 from collections.abc import Callable, Mapping, Sequence
 from dataclasses import asdict, dataclass, field, is_dataclass
@@ -18,6 +19,7 @@ class PrimitiveExecutionError(RuntimeError):
 
 
 _DECLARED_TEXT_MAX_SAFE_INTEGER = 9_007_199_254_740_991
+_DECLARED_TEXT_TEMPLATE_PATTERN = re.compile(r"\{([^}]*)\}")
 
 
 PrimitiveHandler = Callable[[dict[str, Any], dict[str, Any], "PrimitiveContext"], Any]
@@ -784,26 +786,12 @@ def _render_declared_text_line(line: Any, *, current: Any, root: dict[str, Any])
 
 
 def _render_declared_text_template(template: str, *, current: Any, root: dict[str, Any]) -> str:
-    rendered = template
-    for token in _declared_text_template_tokens(template):
+    def replace(match: re.Match[str]) -> str:
+        token = match.group(1)
         found, value = _declared_text_placeholder_value(token, current=current, root=root)
-        rendered = rendered.replace("{" + token + "}", _declared_text_format(value if found else ""))
-    return rendered
-
+        return _declared_text_format(value if found else "")
 
-def _declared_text_template_tokens(template: str) -> list[str]:
-    tokens: list[str] = []
-    index = 0
-    while index < len(template):
-        start = template.find("{", index)
-        if start == -1:
-            break
-        end = template.find("}", start + 1)
-        if end == -1:
-            break
-        tokens.append(template[start + 1 : end])
-        index = end + 1
-    return tokens
+    return _DECLARED_TEXT_TEMPLATE_PATTERN.sub(replace, template)
 
 
 def _declared_text_placeholder_value(token: str, *, current: Any, root: dict[str, Any]) -> tuple[bool, Any]:

tests/test_public_api.py

@@ -1789,6 +1789,8 @@ def test_generated_output_emit_text_views_execute_in_python_and_typescript(tmp_p
             {"name": "active", "arg": "active", "default": False},
             {"name": "score", "arg": "score", "default": 0},
             {"name": "flags", "arg": "flags", "default": []},
+            {"name": "first", "arg": "first", "default": ""},
+            {"name": "second", "arg": "second", "default": ""},
         ]
     )
     operation_path = tmp_path / "contracts" / "operations" / "todo.list.report.json"
@@ -1811,6 +1813,8 @@ def test_generated_output_emit_text_views_execute_in_python_and_typescript(tmp_p
                         "active": {"$value": "active"},
                         "score": {"$value": "score"},
                         "flags": {"$value": "flags"},
+                        "first": {"$value": "first"},
+                        "second": {"$value": "second"},
                     }
                 }
             },
@@ -1833,6 +1837,7 @@ def test_generated_output_emit_text_views_execute_in_python_and_typescript(tmp_p
                             "Profile: {profile}",
                             "Active: {active}",
                             "Score: {score}",
+                            "Single pass: {first} {second}",
                             "Flags: {flags|join:/}",
                             "Items: {items|join:, |empty:(none)}",
                             "Missing: {missing|join:, |empty:(none)}",
@@ -1885,6 +1890,8 @@ def test_generated_output_emit_text_views_execute_in_python_and_typescript(tmp_p
             "active": True,
             "score": 1.0,
             "flags": [True, False, "ok", 2.0],
+            "first": "{second}",
+            "second": "resolved",
         }
         py_text = py_executor.run_operation_callable(py_contract, values)
     finally:
@@ -1910,6 +1917,7 @@ def test_generated_output_emit_text_views_execute_in_python_and_typescript(tmp_p
         "Profile: compact\n"
         "Active: true\n"
         "Score: 1\n"
+        "Single pass: {second} resolved\n"
         "Flags: true/false/ok/2\n"
         "Items: alpha, beta\n"
         "Missing: (none)\n"