tiny.markdown.block

1const std = @import("std");23pub const BlockType = enum {4    paragraph,5    heading1,6    heading2,7    heading3,8    heading4,9    code_block,10    bullet_list,11    numbered_list,12    blockquote,13    horizontal_rule,14};1516pub const Block = struct {17    block_type: BlockType = .paragraph,18    content: []const u8,19    indent: u8 = 0,20    number: ?u16 = null,21    language: ?[]const u8 = null,22};2324pub const Parsed = struct {25    block_type: BlockType,26    content: []const u8,27    number: ?u16,28    indent: u8,29};3031pub fn parseType(line: []const u8) Parsed {32    const indent = markdownIndent(line);33    const trimmed = trimLeft(line, " \t");3435    if (trimmed.len == 0) {36        return .{ .block_type = .paragraph, .content = "", .number = null, .indent = indent };37    }3839    if (trimmed.len >= 3 and (std.mem.startsWith(u8, trimmed, "---") or std.mem.startsWith(u8, trimmed, "***") or std.mem.startsWith(u8, trimmed, "___"))) {40        var all_same = true;41        const first = trimmed[0];42        for (trimmed) |c| {43            if (c != first and c != ' ') {44                all_same = false;45                break;46            }47        }48        if (all_same) {49            return .{ .block_type = .horizontal_rule, .content = "", .number = null, .indent = indent };50        }51    }5253    if (std.mem.startsWith(u8, trimmed, "#### ")) {54        return .{ .block_type = .heading4, .content = trimmed[5..], .number = null, .indent = indent };55    }56    if (std.mem.startsWith(u8, trimmed, "### ")) {57        return .{ .block_type = .heading3, .content = trimmed[4..], .number = null, .indent = indent };58    }59    if (std.mem.startsWith(u8, trimmed, "## ")) {60        return .{ .block_type = .heading2, .content = trimmed[3..], .number = null, .indent = indent };61    }62    if (std.mem.startsWith(u8, trimmed, "# ")) {63        return .{ .block_type = .heading1, .content = trimmed[2..], .number = null, .indent = indent };64    }6566    if (std.mem.startsWith(u8, trimmed, "> ")) {67        return .{ .block_type = .blockquote, .content = trimmed[2..], .number = null, .indent = indent };68    }69    if (std.mem.startsWith(u8, trimmed, ">")) {70        return .{ .block_type = .blockquote, .content = trimmed[1..], .number = null, .indent = indent };71    }7273    if (trimmed.len >= 2 and (trimmed[0] == '-' or trimmed[0] == '*' or trimmed[0] == '+') and trimmed[1] == ' ') {74        return .{ .block_type = .bullet_list, .content = trimmed[2..], .number = null, .indent = indent };75    }7677    if (trimmed.len >= 3) {78        var num_end: usize = 0;79        while (num_end < trimmed.len and trimmed[num_end] >= '0' and trimmed[num_end] <= '9') {80            num_end += 1;81        }82        if (num_end > 0 and num_end < trimmed.len and trimmed[num_end] == '.' and num_end + 1 < trimmed.len and trimmed[num_end + 1] == ' ') {83            const num = std.fmt.parseInt(u16, trimmed[0..num_end], 10) catch 1;84            return .{ .block_type = .numbered_list, .content = trimmed[num_end + 2 ..], .number = num, .indent = indent };85        }86    }8788    if (std.mem.startsWith(u8, trimmed, "```")) {89        return .{ .block_type = .code_block, .content = trimmed[3..], .number = null, .indent = indent };90    }9192    return .{ .block_type = .paragraph, .content = trimmed, .number = null, .indent = indent };93}9495fn markdownIndent(line: []const u8) u8 {96    var columns: usize = 0;97    for (line) |char| {98        switch (char) {99            ' ' => columns += 1,100            '\t' => columns += 4,101            else => break,102        }103    }104    return @intCast(@min(columns / 2, @as(usize, std.math.maxInt(u8))));105}106107fn trimLeft(bytes: []const u8, values: []const u8) []const u8 {108    var start: usize = 0;109    while (start < bytes.len and std.mem.indexOfScalar(u8, values, bytes[start]) != null) start += 1;110    return bytes[start..];111}112113test "parseType heading" {114    const h1 = parseType("# Title");115    try std.testing.expectEqual(BlockType.heading1, h1.block_type);116    try std.testing.expectEqualStrings("Title", h1.content);117118    const h2 = parseType("## Subtitle");119    try std.testing.expectEqual(BlockType.heading2, h2.block_type);120121    const h3 = parseType("### Section");122    try std.testing.expectEqual(BlockType.heading3, h3.block_type);123}124125test "parseType bullet list" {126    const bullet = parseType("- Item");127    try std.testing.expectEqual(BlockType.bullet_list, bullet.block_type);128    try std.testing.expectEqualStrings("Item", bullet.content);129    try std.testing.expectEqual(@as(u8, 0), bullet.indent);130131    const star = parseType("* Another");132    try std.testing.expectEqual(BlockType.bullet_list, star.block_type);133134    const nested = parseType("  - Nested");135    try std.testing.expectEqual(BlockType.bullet_list, nested.block_type);136    try std.testing.expectEqual(@as(u8, 1), nested.indent);137}138139test "parseType numbered list" {140    const num = parseType("1. First");141    try std.testing.expectEqual(BlockType.numbered_list, num.block_type);142    try std.testing.expectEqualStrings("First", num.content);143    try std.testing.expectEqual(@as(?u16, 1), num.number);144145    const num2 = parseType("42. Item");146    try std.testing.expectEqual(@as(?u16, 42), num2.number);147148    const nested = parseType("\t3. Nested");149    try std.testing.expectEqual(@as(?u16, 3), nested.number);150    try std.testing.expectEqual(@as(u8, 2), nested.indent);151}152153test "parseType blockquote" {154    const quote = parseType("> Quote text");155    try std.testing.expectEqual(BlockType.blockquote, quote.block_type);156    try std.testing.expectEqualStrings("Quote text", quote.content);157}158159test "parseType horizontal rule" {160    const hr1 = parseType("---");161    try std.testing.expectEqual(BlockType.horizontal_rule, hr1.block_type);162163    const hr2 = parseType("***");164    try std.testing.expectEqual(BlockType.horizontal_rule, hr2.block_type);165}166167test "parseType paragraph" {168    const para = parseType("Normal text");169    try std.testing.expectEqual(BlockType.paragraph, para.block_type);170    try std.testing.expectEqualStrings("Normal text", para.content);171}172173test "BlockType values" {174    try std.testing.expectEqual(BlockType.paragraph, BlockType.paragraph);175    try std.testing.expectEqual(BlockType.heading1, BlockType.heading1);176    try std.testing.expectEqual(BlockType.code_block, BlockType.code_block);177}

1pub const block = @import("block.zig");