Function detect_array_key_context

src/completion/array_shape.rs:130–249

Detect whether the cursor is in an array key completion context. Recognises patterns like: - `$var['` — empty partial, single-quote - `$var['na` — partial "na", single-quote - `$var["` — empty partial, double-quote - `$var["na` — partial "na", double-quote - `$var[` — no quote yet - `$var['key1']['key2'][`

(
    content: &str,
    position: Position,
)

///
/// Returns `None` if the cursor is not in such a context.
pub(crate) fn detect_array_key_context(
    content: &str,
    position: Position,
) -> Option<ArrayKeyContext> {
    let lines: Vec<&str> = content.lines().collect();
    let line_idx = position.line as usize;
    if line_idx >= lines.len() {
        return None;
    }

    let line = lines[line_idx];
    let chars: Vec<char> = line.chars().collect();
    let col = (position.character as usize).min(chars.len());

    if col == 0 {
        return None;
    }

    // Walk backward from the cursor to find the pattern.
    let mut i = col;

    // 1. Collect partial key text (identifier characters the user has typed).
    let partial_end = i;
    while i > 0 && (chars[i - 1].is_alphanumeric() || chars[i - 1] == '_') {
        i -= 1;
    }
    let partial_start = i;

    // 2. Check for a quote character.
    let quote_char = if i > 0 && (chars[i - 1] == '\'' || chars[i - 1] == '"') {
        let q = chars[i - 1];
        i -= 1;
        Some(q)
    } else {
        None
    };

    // 3. Must have `[` immediately before the quote (or the partial if no quote).
    if i == 0 || chars[i - 1] != '[' {
        return None;
    }
    i -= 1; // skip `[`

    let key_start_col = partial_start as u32;

    // 4. Try to collect chained `['key']` access segments before the
    //    current `[`.  Walk backward through zero or more `]['key']`
    //    or `]["key"]` patterns, collecting the keys.
    let mut prefix_keys: Vec<String> = Vec::new();
    loop {
        // We're now right before the `[` we just consumed.
        // Check if there is a preceding `]` — that would indicate a
        // chained access like `$var['k1']['k2'][`.
        if i == 0 || chars[i - 1] != ']' {
            break;
        }
        // Try to parse the preceding `['key']` segment.
        let saved_i = i;