Description
Resolve an explicitly numeric grid line plus a positive numeric span in a supplied direction; excludes named lines, auto placement and negative end-relative line resolution.
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.
Resolve an explicitly numeric grid line plus a positive numeric span in a supplied direction; excludes named lines, auto placement and negative end-relative line resolution.
When to use this tool
Use this tool to resolve an explicitly numeric grid line plus a positive numeric span in a supplied direction; excludes named lines, auto placement and negative end-relative line resolution.
How to use the tool and how it works
- Enter line, span, backwards using the input definitions below.
- Run the operation. Resolve malformed-input errors before interpreting the result.
- Read result.otherLine. Interpret signs, units, ordering and null values using the rules below.
Validate line as an integer within ±1,000,000 and span as an integer 1–1,000,000. Add span for the forward direction or subtract it when backwards is true.1, 2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| line | Explicit numeric grid line, integer within ±1,000,000; no end-relative resolution occurs. | Finite safe integer satisfying the stated bounds. |
| span | Positive integer number of grid tracks, 1–1,000,000. | Finite safe integer satisfying the stated bounds. |
| backwards | True subtracts span from line; false adds it. | Boolean true or false. |
| Output field | Interpretation |
|---|---|
| result | Object containing the fields below. |
| result.otherLine | Resolved arithmetic grid endpoint before any full grid-line interpretation. |
{
"input": {
"line": 3,
"span": 2,
"backwards": false
},
"output": {
"result": {
"otherLine": 5
}
}
}Limitations and assumptions
- This is numeric line arithmetic, not resolution of negative end-relative grid lines, named lines or auto placement.
- 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
Similar or alternative tools
- CSS Grid Area Rectangle Validity
Audit supplied nonempty whitespace-tokenized grid template area rows for rectangular named regions; dot means empty, not a complete CSS string/token parser.
- CSS Animation List Slot Pairing
Pair explicit animation names with cyclic duration/delay lists; no shorthand parsing, timing interpolation or special all/none expansion.