CSS Custom Property Reference Inventory

Description

Inventory unescaped ASCII var() reference names including nested fallbacks, ignoring quoted strings; existing variable-parser extracts declarations instead. Comment-free balanced CSS subset.

CSS combines token syntax, property-specific value rules and layout/cascade processing. These are separate layers: splitting a declaration does not establish that its value is valid, and arithmetic on resolved lengths does not perform browser layout. Each tool here handles an explicit numeric representation or a stated lexical subset.

Inventory unescaped ASCII var() reference names including nested fallbacks, ignoring quoted strings; existing variable-parser extracts declarations instead. Comment-free balanced CSS subset.

When to use this tool

Use this tool to inventory unescaped ASCII var() reference names including nested fallbacks, ignoring quoted strings; existing variable-parser extracts declarations instead. Comment-free balanced CSS subset.

How to use the tool and how it works

Enter value using the input definitions below.
Run the operation. Resolve malformed-input errors before interpreting the result.
Read result.references. Interpret signs, units, ordering and null values using the rules below.

Validate balanced comment-free structure and scan outside quoted strings for literal lowercase var( tokens not preceded by an identifier character. Capture each restricted ASCII --name and the var token’s UTF-16 position, including nested fallbacks.^{[1, 2]}

Input field	Meaning and units	Accepted input
value	CSS-subset value text; quoted strings and grouping follow the stated lexical rules.	Text, at most 8,192 UTF-16 code units; the stated grammar and narrower limits also apply.

Output field	Interpretation
result	Object containing the fields below.
result.references	Source-order custom-property references with var token positions.

json

{
  "input": {
    "value": "var(--a, var(--b)) \"var(--c)\""
  },
  "output": {
    "result": {
      "references": [
        {
          "name": "--a",
          "position": 0
        },
        {
          "name": "--b",
          "position": 9
        }
      ]
    }
  }
}

Limitations and assumptions

This inventories references rather than declarations or resolved values. Escaped function/name syntax, comments and complete CSS substitution semantics are unsupported.
Lengths and times must already be resolved to consistent numeric units. Lexical helpers intentionally support smaller grammars than a full browser CSS parser; malformed supported-subset input causes an error.
Every declared top-level input is required and unknown fields are rejected. Ordinary strings are limited to 8,192 UTF-16 code units and lists to 128 entries, with tighter operation-specific bounds where stated. JSON text has bounded nesting and node counts.
Numeric outputs must be finite and within the absolute safe-integer magnitude; exact larger integers use decimal text. Source positions are zero-based UTF-16 offsets and span ends are exclusive unless a different convention is explicitly stated.

Alternative or Complementary methods

Use a full CSS parser or browser style/layout APIs when escape handling, error recovery, computed styles or the full cascade matter. These tools expose focused transformations and audits of supplied data.

References

CSS Custom Properties: Variables — W3C
Tool behavior and example: CSS Custom Property Reference Inventory — tool.io

Similar or alternative tools

CSS Custom Property Name Token Audit
Audit a deliberately restricted ASCII custom-property token grammar -- followed by letters/digits/underscore/dash; not full CSS identifier validation.
CSS Duplicate Property Table
Audit declaration property duplicates with ordinary ASCII property folding and case-sensitive custom-property names; not a cascade engine.