Function parse_with 

pub fn parse_with(
    v: &Value,
    refs: Option<&mut NameRefs<'_>>,
) -> Result<Gradient, String>

Reads a gradient from plain data, the form every binding carries:

• { to = "bottom", stops = {…} } — a side or a corner (Side);
• { angle = 0.125, stops = {…} } — turns clockwise from east;
• { radial = true, at = {0.5, 0}, stops = {…} } — at optional.

No to, angle or radial is to = "bottom". A stop is a colour — 0xRRGGBBAA, "#hex", or with refs a $name — or a {colour, position} pair. A $name that misses is remembered on the refs for the binding to raise, and its stop is left out, as a miss leaves any slot: fewer than two stops in the list is an error, but a list left with fewer once the misses are out parses, and draws nothing (ADR 0042’s amendment, weighed again for backlog RG118).