Block

const Block = struct

File

Code

const Block = struct {
    tag: Tag,
    data: Data,
    extra_start: usize,
    string_start: usize,

    const Tag = enum {
        /// Data is `list`.
        list,
        /// Data is `list_item`.
        list_item,
        /// Data is `table`.
        table,
        /// Data is `none`.
        table_row,
        /// Data is `heading`.
        heading,
        /// Data is `code_block`.
        code_block,
        /// Data is `none`.
        blockquote,
        /// Data is `none`.
        paragraph,
        /// Data is `none`.
        thematic_break,
    };

    const Data = union {
        none: void,
        list: struct {
            marker: ListMarker,
            /// Between 0 and 999,999,999, inclusive.
            start: u30,
            tight: bool,
            last_line_blank: bool = false,
        },
        list_item: struct {
            continuation_indent: usize,
        },
        table: struct {
            column_alignments_buffer: [max_table_columns]Node.TableCellAlignment,
            column_alignments_len: usize,
        },
        heading: struct {
            /// Between 1 and 6, inclusive.
            level: u3,
        },
        code_block: struct {
            tag: StringIndex,
            fence_len: usize,
            indent: usize,
        },

        const ListMarker = enum {
            @"-",
            @"*",
            @"+",
            number_dot,
            number_paren,
        };
    };

    const ContentType = enum {
        blocks,
        inlines,
        raw_inlines,
        nothing,
    };

    fn canAccept(b: Block) ContentType {
        return switch (b.tag) {
            .list,
            .list_item,
            .table,
            .blockquote,
            => .blocks,

            .heading,
            .paragraph,
            => .inlines,

            .code_block,
            => .raw_inlines,

            .table_row,
            .thematic_break,
            => .nothing,
        };
    }

    /// Attempts to continue `b` using the contents of `line`. If successful,
    /// returns the remaining portion of `line` to be considered part of `b`
    /// (e.g. for a blockquote, this would be everything except the leading
    /// `>`). If unsuccessful, returns null.
    fn match(b: Block, line: []const u8) ?[]const u8 {
        const unindented = mem.trimStart(u8, line, " \t");
        const indent = line.len - unindented.len;
        return switch (b.tag) {
            .list => line,
            .list_item => if (indent >= b.data.list_item.continuation_indent)
                line[b.data.list_item.continuation_indent..]
            else if (unindented.len == 0)
                // Blank lines should not close list items, since there may be
                // more indented contents to follow after the blank line.
                ""
            else
                null,
            .table => if (unindented.len > 0) line else null,
            .table_row => null,
            .heading => null,
            .code_block => code_block: {
                const trimmed = mem.trimEnd(u8, unindented, " \t");
                if (mem.indexOfNone(u8, trimmed, "`") != null or trimmed.len != b.data.code_block.fence_len) {
                    const effective_indent = @min(indent, b.data.code_block.indent);
                    break :code_block line[effective_indent..];
                } else {
                    break :code_block null;
                }
            },
            .blockquote => if (mem.startsWith(u8, unindented, ">"))
                unindented[1..]
            else
                null,
            .paragraph => if (unindented.len > 0) line else null,
            .thematic_break => null,
        };
    }
}