Files
ai-app/app/androidApp/src/main/kotlin/com/example/aiapp/MarkdownSyntax.kt
T
irisandClaude Opus 5 edc39c7371 Thin the app's comments
The same pass the server had, on the Kotlin side: comments restating what
the code says are gone, and the ones recording a measurement, a constraint
or an incident are kept but cut to a few lines each. 6540 comment lines to
5674, and 920 lines off the app.

Two doc comments had drifted onto the item above the one they describe --
`contextAfter`'s onto `sessionWorking` in Events.kt, and `UsageMonitor`'s
equivalent on the server was fixed in the previous commit. Each is back on
its own item, which is the only non-comment line this diff moves.

The comments are reflowed to the column limit at their own indentation:
several were written wide, and ktfmt re-wrapped them into lines holding a
single orphan word. `/tmp` script, not kept -- ktfmt is idempotent over the
result, which is the check.

Left alone deliberately: this codebase's remaining comment density is high
because the comments carry things the code cannot say -- what a null means,
what a number was measured against, which bug a guard exists for. Of the
238 one-line doc comments in the app, five were pure restatement of the
name and were removed; the rest each say something the signature does not.

ktfmtFormat, compileDebugKotlin, lintDebug and testDebugUnitTest pass;
cargo test (127), clippy --all-targets and fmt still clean.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-04 16:20:16 -04:00

451 lines
18 KiB
Kotlin

package com.example.aiapp
/**
* Markdown read into the spans that carry a colour -- a ```markdown fence in a reply, and a `.md`
* file in the viewer.
*
* Its own scanner rather than a row of [Rules] because markdown has neither keywords nor strings:
* what a character means depends on where it sits. A `#` opens a heading at the start of a line and
* is an ordinary character three words in; a `*` opens emphasis only if something closes it on the
* same line. The token scanner cannot ask either question.
*
* Structure is read a line at a time and each line's prose left to right, so every decision is made
* inside one line -- except the two that are not. A fenced block is state carried forward, so an
* unclosed fence colours the rest of the text, which is what it looks like while somebody is
* writing it. A table is found by its delimiter row (`|---|---|`), the only line of one that cannot
* be anything else, and its header is the line before that -- the one place here that looks ahead.
*
* What is deliberately *not* recognised: an indented code block. Four spaces after a blank line is
* one, four spaces after a bullet is a list item's second paragraph, and the two are told apart by
* what came before. Colouring the wrong one as code is a mistake the reader cannot see.
*
* Like [scan], the spans come out ordered, non-overlapping and inside the text by construction.
*/
fun scanMarkdown(code: String): List<Span> = MarkdownScanner(code).run()
/** The characters an unordered list may be bulleted with. */
private const val BULLETS = "-*+"
/** The characters a thematic break, or a setext heading's underline, can be drawn with. */
private const val RULE_MARKERS = "-*_="
/** The characters that can open emphasis, strong emphasis or a strikethrough. */
private const val EMPHASIS = "*_~"
/** Characters that end a bare URL wherever they appear, and ones only trimmed off the end. */
private const val URL_STOPS = "<>\"'`|"
private const val URL_TRAILING = ".,:;!?"
private class MarkdownScanner(private val code: String) {
private val spans = ArrayList<Span>()
fun run(): List<Span> {
var at = 0
// The delimiter run that opened the fenced block we are inside, or null between them.
var fence: String? = null
// Whether the row above was part of a table, which is what makes this one a body row.
var table = false
while (at <= code.length) {
val end = lineEnd(at)
val open = fence
if (open != null) {
// The content and the closing line alike: a fence is one block of code, and its own
// delimiters belong to it the way a string's quotes belong to the string.
emit(at, end, Kind.STRING)
if (closesFence(at, end, open)) fence = null
} else {
val opened = opensFence(at, end)
fence = opened
if (opened != null) table = false else table = row(at, end, table)
}
if (end == code.length) break
at = end + 1
}
return spans
}
/** The end of the line beginning at [at]: the newline, or the end of the text. */
private fun lineEnd(at: Int): Int {
val newline = code.indexOf('\n', at)
return if (newline < 0) code.length else newline
}
/**
* One line that is not inside a fence, and whether the table it may be part of is still open.
*
* A table is recognised by its delimiter row, the only line of one that cannot be anything
* else. That row comes *after* the header it belongs to, so the header is found by looking one
* line ahead -- the single piece of lookahead here, and cheaper than colouring every `|` in the
* document, which would mark the pipes in a shell command written in a paragraph.
*/
private fun row(start: Int, end: Int, table: Boolean): Boolean {
if (tableDelimiter(start, end)) {
emit(indented(start, end), end, Kind.MARK)
return true
}
val header = end < code.length && tableDelimiter(end + 1, lineEnd(end + 1))
if ((table || header) && hasPipe(start, end)) {
tableRow(start, end)
return true
}
structure(start, end)
return false
}
/** A line of nothing but pipes, dashes, alignment colons and space, with one of each needed. */
private fun tableDelimiter(start: Int, end: Int): Boolean {
var dashes = false
var pipes = false
for (at in indented(start, end) until end) {
when (code[at]) {
'-' -> dashes = true
'|' -> pipes = true
':',
' ',
'\t' -> {}
else -> return false
}
}
return dashes && pipes
}
private fun hasPipe(start: Int, end: Int): Boolean {
var at = start
while (at < end) {
if (code[at] == '\\') at += 2 else if (code[at] == '|') return true else at++
}
return false
}
/** A table row: the pipes are the structure, and what is between them is prose. */
private fun tableRow(start: Int, end: Int) {
var at = indented(start, end)
var cell = at
while (at < end) {
when (code[at]) {
'\\' -> at += 2
'|' -> {
inline(cell, at)
emit(at, at + 1, Kind.MARK)
at++
cell = at
}
else -> at++
}
}
inline(cell, end)
}
/**
* Spans, coalesced with the one before when they touch and agree. Worth doing here rather than
* leaving it to the caller: the line scanner emits per marker and per word, so a heading would
* otherwise arrive as a dozen abutting spans of one colour.
*/
private fun emit(start: Int, end: Int, kind: Kind) {
if (end <= start) return
val last = spans.lastOrNull()
if (last != null && last.kind == kind && last.end == start) {
spans[spans.size - 1] = Span(last.start, end, kind)
} else {
spans.add(Span(start, end, kind))
}
}
/** The first character of the line at or after [start] that is not indentation. */
private fun indented(start: Int, end: Int): Int {
var at = start
while (at < end && (code[at] == ' ' || code[at] == '\t')) at++
return at
}
/** The run of backticks or tildes that could open or close a fence on this line, or null. */
private fun fenceRun(start: Int, end: Int): IntRange? {
val at = indented(start, end)
if (at == end) return null
val marker = code[at]
if (marker != '`' && marker != '~') return null
var run = at
while (run < end && code[run] == marker) run++
return if (run - at >= 3) at until run else null
}
/** Draws an opening fence line and answers its delimiter, or null if this is not one. */
private fun opensFence(start: Int, end: Int): String? {
val run = fenceRun(start, end) ?: return null
emit(run.first, run.last + 1, Kind.STRING)
// The info word is what the fence is a fence *of*, which is metadata about the block rather
// than part of it.
emit(indented(run.last + 1, end), end, Kind.METADATA)
return code.substring(run.first, run.last + 1)
}
/**
* Whether this line closes a fence opened by [open]: the same character, at least as many of
* them, and nothing else on the line -- so a longer run closes a shorter one and a line of
* backticks with a word after it does not close anything.
*/
private fun closesFence(start: Int, end: Int, open: String): Boolean {
val run = fenceRun(start, end) ?: return false
if (code[run.first] != open[0] || run.last + 1 - run.first < open.length) return false
return indented(run.last + 1, end) == end
}
/** One ordinary line: what its opening characters make it, and then its prose. */
private fun structure(start: Int, end: Int) {
var at = indented(start, end)
// Quote markers come before everything else and can be several deep, and what follows one
// is an ordinary line again -- a heading inside a quote is still a heading.
while (at < end && code[at] == '>') {
at++
emit(at - 1, at, Kind.MARK)
at = indented(at, end)
}
if (at == end) return
if (heading(at, end) || thematicBreak(at, end)) return
inline(bullet(at, end), end)
}
/** `#` to `######` and a space. Without the space it is a word beginning with a hash. */
private fun heading(start: Int, end: Int): Boolean {
var at = start
while (at < end && code[at] == '#') at++
val depth = at - start
if (depth !in 1..6) return false
if (at < end && code[at] != ' ' && code[at] != '\t') return false
emit(start, end, Kind.KEYWORD)
return true
}
/**
* A line made of one repeated rule character and nothing else.
*
* `---`, `***` and `___` are thematic breaks; `===` and `---` are also the underline of a
* setext heading. The two are the same line to look at and mean the same thing to a reader, so
* they get one appearance rather than a lookback. One `=` is enough because a setext underline
* may be a single character; a break needs three, which keeps a `- ` bullet out of here.
*/
private fun thematicBreak(start: Int, end: Int): Boolean {
val marker = code[start]
if (marker !in RULE_MARKERS) return false
var seen = 0
for (at in start until end) {
val character = code[at]
if (character == marker) seen++ else if (!character.isWhitespace()) return false
}
if (seen < if (marker == '=') 1 else 3) return false
emit(start, end, Kind.MARK)
return true
}
/** Draws a list marker if the line opens with one, and answers where the item's text starts. */
private fun bullet(start: Int, end: Int): Int {
val marker = code[start]
if (marker in BULLETS && spaceOrEnd(start + 1, end)) {
emit(start, start + 1, Kind.MARK)
return indented(start + 1, end)
}
var digits = start
while (digits < end && code[digits].isDigit()) digits++
val delimiter = code.getOrNull(digits)
if (
digits > start && (delimiter == '.' || delimiter == ')') && spaceOrEnd(digits + 1, end)
) {
emit(start, digits + 1, Kind.MARK)
return indented(digits + 1, end)
}
return start
}
private fun spaceOrEnd(at: Int, end: Int) = at >= end || code[at] == ' ' || code[at] == '\t'
/**
* The inline forms, left to right.
*
* Every branch answers a position strictly after [start] of its call, so this terminates
* whether or not the form it was looking at turned out to be one.
*/
private fun inline(start: Int, end: Int) {
var at = start
while (at < end) {
val character = code[at]
at =
when {
// A backslash takes the character after it out of the running entirely, which
// is how `\*` stays an asterisk rather than opening emphasis.
character == '\\' -> at + 2
character == '`' -> codeSpan(at, end)
character == '[' -> link(at, at, end)
character == '!' && code.getOrNull(at + 1) == '[' -> link(at, at + 1, end)
character == '<' -> autolink(at, end)
character in EMPHASIS -> emphasis(at, end)
else -> url(at, end) ?: (at + 1)
}
}
}
/**
* `` `code` ``, closed by a run of exactly as many backticks as opened it. That count is what
* lets a span hold a backtick of its own, and why the search skips over a shorter or longer run
* rather than stopping at the first backtick.
*/
private fun codeSpan(start: Int, end: Int): Int {
var open = start
while (open < end && code[open] == '`') open++
val ticks = open - start
var at = open
while (at < end) {
if (code[at] != '`') {
at++
continue
}
var close = at
while (close < end && code[close] == '`') close++
if (close - at == ticks) {
emit(start, close, Kind.STRING)
return close
}
at = close
}
// Nothing closes it on this line, so those were ordinary backticks.
return open
}
/**
* `[text](destination)`, and the same with a leading `!` for an image.
*
* The text is drawn as prose -- it is what the reader reads -- so only the brackets around it
* are marked, and the destination is metadata. A `[text]` with no destination after it is left
* plain, because that is what a reference link and a bracketed aside look like.
*/
private fun link(start: Int, bracket: Int, end: Int): Int {
var depth = 0
var close = bracket
while (close < end) {
when (code[close]) {
'\\' -> close++
'[' -> depth++
']' -> {
depth--
if (depth == 0) break
}
}
close++
}
if (close >= end) return start + 1
val destination = close + 1
if (code.getOrNull(destination) != '(') return start + 1
val paren = code.indexOf(')', destination)
if (paren < 0 || paren >= end) return start + 1
emit(start, bracket + 1, Kind.MARK)
inline(bracket + 1, close)
emit(close, destination, Kind.MARK)
emit(destination, paren + 1, Kind.METADATA)
return paren + 1
}
/**
* `<https://example.com>` and `<name@example.com>`, drawn as the destination they are.
*
* The angle brackets have to hold no whitespace and something that makes an address of it -- a
* scheme's colon or an at sign -- which is what keeps an HTML tag out.
*/
private fun autolink(start: Int, end: Int): Int {
var at = start + 1
var addressed = false
while (at < end) {
val character = code[at]
if (character.isWhitespace() || character == '<') return start + 1
if (character == '>') {
if (!addressed) return start + 1
emit(start, at + 1, Kind.METADATA)
return at + 1
}
if (character == ':' || character == '@') addressed = true
at++
}
return start + 1
}
/**
* A bare `scheme://…` written in prose, or null if one does not start here.
*
* A scheme and `://` rather than a list of them, so `ftp`, `file` and `ssh` need no entry.
*
* Where it ends is the part worth stating: the sentence's punctuation is not the address, so a
* trailing `.` or `,` is given back, and so is a closing bracket unless one opened inside the
* URL -- otherwise a link in parentheses loses its `)`. A pipe stops it too, because a URL in a
* table cell must not swallow the cell's edge.
*/
private fun url(start: Int, end: Int): Int? {
if (start > 0 && isWord(code[start - 1])) return null
var scheme = start
while (scheme < end && code[scheme].isLetter()) scheme++
if (scheme == start || !code.startsWith("://", scheme)) return null
val body = scheme + 3
var at = body
var openers = 0
var closers = 0
while (at < end && !code[at].isWhitespace() && code[at] !in URL_STOPS) {
if (code[at] == '(') openers++ else if (code[at] == ')') closers++
at++
}
while (at > body) {
val last = code[at - 1]
if (last in URL_TRAILING) at--
else if (last == ')' && closers > openers) {
closers--
at--
} else break
}
if (at == body) return null
emit(start, at, Kind.METADATA)
return at
}
/**
* `*emph*`, `**strong**`, `_emph_` and `~~struck~~`, drawn markers and all -- which is how the
* token scanner draws a string: the quotes are part of the thing.
*
* The two guards keep this off code that happens to be in a paragraph: the opener must be
* followed by something to emphasise and the closer preceded by something emphasised, so `a * b
* * c` opens nothing and neither does the `*p = *q` of a C fragment. Underscores may not start
* or end inside a word, or every `snake_case_name` would be half emphasised.
*/
private fun emphasis(start: Int, end: Int): Int {
val marker = code[start]
var open = start
while (open < end && code[open] == marker) open++
val length = open - start
if (marker == '~' && length != 2) return open
if (length > 3) return open
if (open == end || code[open].isWhitespace()) return open
if (marker == '_' && start > 0 && isWord(code[start - 1])) return open
var at = open
while (at < end) {
if (code[at] == '\\') {
at += 2
continue
}
if (code[at] != marker) {
at++
continue
}
var close = at
while (close < end && code[close] == marker) close++
val finish = at + length
if (
close - at >= length &&
!code[at - 1].isWhitespace() &&
!(marker == '_' && finish < end && isWord(code[finish]))
) {
emit(start, finish, Kind.LITERAL)
return finish
}
at = close
}
return open
}
}
private fun isWord(character: Char) = character.isLetterOrDigit() || character == '_'