This creates a smaller state machine helper type for softness coalescing, which does not own the resulting nodes. While this creates a bit more duplication in stack and par builder, it makes it a lot easier to integrate additional logic into the paragraph builder.
Furthermore:
- Line breaks are now "hard", that is, not coalesced with each other.
- Text nodes with equal style are now merged allowing for example `f{}i` to form a ligature.
This adds overridable functions that markup desugars into. Specifically:
- \ desugars into linebreak
- Two newlines desugar into parbreak
- * desugars into strong
- _ desugars into emph
- = .. desugars into heading
- `..` desugars into raw
- New naming scheme
- TextNode instead of NodeText
- CallExpr instead of ExprCall
- ...
- Less glob imports
- Removes Value::Args variant
- Removes prelude
- Renames Layouted to Fragment
- Moves font into env
- Moves shaping into layout
- Moves frame into separate module
Adds top-edge and bottom-edge parameters to the font function. These define how
the box around a word is computed. The possible values are:
- ascender
- cap-height (default top edge)
- x-height
- baseline (default bottom edge)
- descender
The defaults are chosen so that it's easy to create good-looking designs with
vertical alignment. Since they are much tighter than what most other software
uses by default, the default leading had to be increased to 50% of the font size
and paragraph spacing to 100% of the font size.
The values cap-height and x-height fall back to ascender in case they are zero
because this value may occur in fonts that don't have glyphs with cap- or
x-height (like Twitter Color Emoji). Since cap-height is the default top edge,
doing no fallback would break things badly.
Removes softness in favor of a simple boolean for pages and a more finegread u8
for spacing. This is needed to make paragraph spacing consume line spacing
created by hard line breaks.
- The execution context is a lot more structured: Instead of a magic stack of arbitrary objects there are static objects for pages, stacks and paragraphs
- Page softness/keeping mechanic is now a lot simpler than before
This makes expansion behaviour inheritable by placing it into the area and passing it down during layouting instead of computing some approximation of what we want during execution.
Supports:
- Closure syntax: `(x, y) => z`
- Shorthand for a single argument: `x => y`
- Function syntax: `let f(x) = y`
- Capturing of variables from the environment
- Error messages for too few / many passed arguments
Does not support:
- Named arguments
- Variadic arguments with `..`
- Identifiers are now evaluated as variables instead of being plain values
- Constants like `left` or `bold` are stored as dynamic values containing the respective rust types
- We now distinguish between arrays and dictionaries to make things more intuitive (at the cost of a bit more complex parsing)
- Spans were removed from collections (arrays, dictionaries), function arguments still have spans for the top-level values to enable good diagnostics
- Make page break behaviour more consistent
- Allow skipping reference image testing for single tests with `// compare-ref: false` (useful for tests which only check error messages)
Doesn't layout contents into a box anymore, instead layouting inline in the parent context. Also makes axis inferring for center alignents smarter (just because I had fun doing it). It's unsure whether we want to keep it because it might be confusing.
- In addition to syntax trees there are now `Value`s, which syntax trees can be evaluated into (e.g. the tree is `5+5` and the value is `10`)
- Parsing is completely pure, function calls are not parsed into nodes, but into simple call expressions, which are resolved later
- Functions aren't dynamic nodes anymore, but simply functions which receive their arguments as a table and the layouting context
- Functions may return any `Value`
- Layouting is powered by functions which return the new `Commands` value, which informs the layouting engine what to do
- When a function returns a non-`Commands` value, the layouter simply dumps the value into the document in monospace
Laurenz
Martin