Single Pass Literal Template Renderer

Render a single pass of literal placeholders from an explicit unique name/value table; inserted placeholders are not recursively expanded.

Description

Render a single pass of literal placeholders from an explicit unique name/value table; inserted placeholders are not recursively expanded.

Literal template substitution replaces named placeholders without executing expressions. A single pass prevents replacement text from introducing new substitutions during the same run.

When to use this tool

Render a single pass of literal placeholders from an explicit unique name/value table; inserted placeholders are not recursively expanded.

Prepare the supplied text, openMarker, closeMarker, names, values fields for this operation.
Compare the complete example with the representation used by your own input before carrying the result into another step.

How to use the tool and how it works

Enter text, openMarker, closeMarker, names, values. Use the exact text syntax, units and index conventions explained below.
Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
Read result.text, result.unresolvedNames. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.

Require nonempty markers and aligned names/values with distinct nonblank names. Scan the original text for an opener followed by the next closer, replace known names, retain unknown placeholders and list their names.^[1]

Input field	Meaning and representation	Accepted input
text	text.	Text; at most 8,192 UTF-16 code units, subject to the grammar above
openMarker	open marker.	Text; at most 8,192 UTF-16 code units, subject to the grammar above
closeMarker	close marker.	Text; at most 8,192 UTF-16 code units, subject to the grammar above
names	names.	At most 128 strings, each at most 128 UTF-16 code units
values	values.	At most 128 strings, each at most 128 UTF-16 code units

Output field	Interpretation
result	Object containing the named outputs below.
result.text	The text value under the stated formula or text convention.
result.unresolvedNames	The unresolved names list in the ordering and representation described above.

json

{
  "input": {
    "text": "{a}{b}",
    "openMarker": "{",
    "closeMarker": "}",
    "names": [
      "a"
    ],
    "values": [
      "{b}"
    ]
  },
  "output": {
    "result": {
      "text": "{b}{b}",
      "unresolvedNames": [
        "b"
      ]
    }
  }
}

Limitations and assumptions

Inserted values are never rescanned. An unclosed opener leaves the remaining original text unchanged; there is no escaping, nesting, evaluation or output-context sanitization.
Text offsets and lengths use UTF-16 code units unless explicitly described as bytes or code points. CRLF, CR and LF are recognized as line endings; a terminal newline creates a final empty line in the shared line model.
Every declared top-level field is required and unexpected fields are rejected. Numeric inputs must be finite; ordinary text fields are bounded to 8,192 UTF-16 code units, with tighter operation-specific limits where stated.
Ordinary string lists have at most 128 entries of at most 128 code units each; numeric lists and matrices have separate bounded size checks. Nonfinite results and excessively large serialized outputs are rejected.
Indexes are zero-based and spans have an exclusive end unless explicitly stated otherwise. A valid false, null or empty-list result is distinct from malformed input.

Alternative or Complementary methods

Use a parser or language-aware editor when quoting, syntax or nested constructs matter. For plain text transforms, keep UTF-16 offsets, Unicode code points, grapheme clusters and UTF-8 byte offsets distinct; apply changes to the same source version used to calculate spans.

References

Tool behavior and example: Single Pass Literal Template Renderer — tool.io

Similar or alternative tools

Single Pair Delimiter Repair Hints
Provide literal single-pair delimiter insertion hints with unmatched offsets; quotes, escapes and cross-type nesting are outside scope.
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Strip one complete nonoverlapping enclosing literal wrapper, never internal or partial matches.