tiny.termtex.layout

1const std = @import("std");2const ast = @import("ast.zig");3const operator = @import("operator.zig");45pub const Box = struct {6    width: usize,7    height: usize,8    baseline: usize,9    cells: []Cell,1011    pub fn at(self: Box, x: usize, y: usize) Cell {12        return self.cells[y * self.width + x];13    }1415    pub fn set(self: *Box, x: usize, y: usize, cell: Cell) void {16        self.cells[y * self.width + x] = cell;17    }18};1920const Cell = []const u8;21const space = " ";2223pub fn layout(arena: std.mem.Allocator, expr: *const ast.Expr) std.mem.Allocator.Error!Box {24    return switch (expr.*) {25        .row => |items| layoutRow(arena, items),26        .text => |value| textBox(arena, value),27        .operator => |value| layout(arena, value.body),28        .space => |value| layoutSpace(arena, value),29        .fraction => |value| layoutFraction(arena, value),30        .sqrt => |value| layoutSqrt(arena, value),31        .scripts => |value| layoutScripts(arena, value),32        .accent => |value| layoutAccent(arena, value),33        .grid => |value| layoutGrid(arena, value),34        .annotation => |value| layoutAnnotation(arena, value),35        .delimited => |value| layoutDelimited(arena, value),36    };37}3839pub fn rows(arena: std.mem.Allocator, value: Box) std.mem.Allocator.Error![]const []const u8 {40    const out = try arena.alloc([]const u8, value.height);41    for (0..value.height) |y| {42        var end = value.width;43        while (end > 0 and std.mem.eql(u8, value.at(end - 1, y), space)) end -= 1;44        var line: std.ArrayListUnmanaged(u8) = .empty;45        for (0..end) |x| try line.appendSlice(arena, value.at(x, y));46        out[y] = try line.toOwnedSlice(arena);47    }48    return out;49}5051fn layoutRow(arena: std.mem.Allocator, items: []const *ast.Expr) std.mem.Allocator.Error!Box {52    if (items.len == 0) return makeBox(arena, 0, 1, 0);53    const children = try arena.alloc(Box, items.len);54    var width: usize = 0;55    var baseline: usize = 0;56    var descent: usize = 0;57    for (items, 0..) |item, index| {58        children[index] = try layout(arena, item);59        width += children[index].width;60        baseline = @max(baseline, children[index].baseline);61        descent = @max(descent, children[index].height - children[index].baseline - 1);62    }63    var out = try makeBox(arena, width, baseline + descent + 1, baseline);64    var x: usize = 0;65    for (children) |child| {66        putBox(&out, x, baseline - child.baseline, child);67        x += child.width;68    }69    return out;70}7172fn layoutSpace(arena: std.mem.Allocator, value: ast.Space) std.mem.Allocator.Error!Box {73    return makeBox(arena, spaceCells(value), 1, 0);74}7576fn layoutFraction(arena: std.mem.Allocator, value: ast.Fraction) std.mem.Allocator.Error!Box {77    const numerator = try layout(arena, value.numerator);78    const denominator = try layout(arena, value.denominator);79    const width = @max(numerator.width, denominator.width) + 2;80    var out = try makeBox(arena, width, numerator.height + denominator.height + 1, numerator.height);81    putBox(&out, centered(width, numerator.width), 0, numerator);82    for (0..width) |x| out.set(x, numerator.height, "─");83    putBox(&out, centered(width, denominator.width), numerator.height + 1, denominator);84    return out;85}8687fn layoutSqrt(arena: std.mem.Allocator, value: ast.Radical) std.mem.Allocator.Error!Box {88    const body = try layout(arena, value.body);89    const index = if (value.index) |expr| try layout(arena, expr) else null;90    const prefix = if (index) |idx| @max(idx.width, @as(usize, 1)) else 1;91    const height = body.height + 1;92    var out = try makeBox(arena, prefix + body.width + 1, height, body.baseline + 1);93    if (index) |idx| putBox(&out, prefix - idx.width, 0, idx);94    out.set(prefix - 1, out.baseline, "√");95    for (0..body.width + 1) |x| out.set(prefix + x, 0, "─");96    putBox(&out, prefix + 1, 1, body);97    return out;98}99100fn layoutScripts(arena: std.mem.Allocator, value: ast.Scripts) std.mem.Allocator.Error!Box {101    if (operator.limitsBase(value.base)) return layoutLimits(arena, value);102    const base = try layout(arena, value.base);103    const sup = if (value.sup) |expr| try layout(arena, expr) else null;104    const sub = if (value.sub) |expr| try layout(arena, expr) else null;105    const script_width = @max(if (sup) |box| box.width else 0, if (sub) |box| box.width else 0);106    const top = if (sup) |box| box.height else 0;107    const bottom = if (sub) |box| box.height else 0;108    var out = try makeBox(arena, base.width + script_width, top + base.height + bottom, top + base.baseline);109    if (sup) |box| putBox(&out, base.width, 0, box);110    putBox(&out, 0, top, base);111    if (sub) |box| putBox(&out, base.width, top + base.height, box);112    return out;113}114115fn layoutLimits(arena: std.mem.Allocator, value: ast.Scripts) std.mem.Allocator.Error!Box {116    const base = try layout(arena, value.base);117    const sup = if (value.sup) |expr| try layout(arena, expr) else null;118    const sub = if (value.sub) |expr| try layout(arena, expr) else null;119    const width = @max(base.width, @max(if (sup) |box| box.width else 0, if (sub) |box| box.width else 0));120    const top = if (sup) |box| box.height else 0;121    const bottom = if (sub) |box| box.height else 0;122    var out = try makeBox(arena, width, top + base.height + bottom, top + base.baseline);123    if (sup) |box| putBox(&out, centered(width, box.width), 0, box);124    putBox(&out, centered(width, base.width), top, base);125    if (sub) |box| putBox(&out, centered(width, box.width), top + base.height, box);126    return out;127}128129fn layoutAccent(arena: std.mem.Allocator, value: ast.Accent) std.mem.Allocator.Error!Box {130    const body = try layout(arena, value.body);131    if (value.mark == .underline) {132        var out = try makeBox(arena, body.width, body.height + 1, body.baseline);133        putBox(&out, 0, 0, body);134        for (0..body.width) |x| out.set(x, body.height, "─");135        return out;136    }137    var out = try makeBox(arena, body.width, body.height + 1, body.baseline + 1);138    if (body.width != 0) {139        switch (value.mark) {140            .bar => for (0..body.width) |x| out.set(x, 0, "─"),141            .hat => out.set(centered(body.width, 1), 0, "^"),142            .vec => out.set(centered(body.width, 1), 0, "→"),143            .dot => out.set(centered(body.width, 1), 0, "˙"),144            .underline => unreachable,145            .tilde => out.set(centered(body.width, 1), 0, "~"),146            .check => out.set(centered(body.width, 1), 0, "ˇ"),147            .breve => out.set(centered(body.width, 1), 0, "˘"),148            .ddot => out.set(centered(body.width, 1), 0, "¨"),149            .acute => out.set(centered(body.width, 1), 0, "´"),150            .grave => out.set(centered(body.width, 1), 0, "`"),151            .ring => out.set(centered(body.width, 1), 0, "˚"),152            .overleft => out.set(centered(body.width, 1), 0, "←"),153            .overleftright => out.set(centered(body.width, 1), 0, "↔"),154        }155    }156    putBox(&out, 0, 1, body);157    return out;158}159160fn layoutAnnotation(arena: std.mem.Allocator, value: ast.Annotation) std.mem.Allocator.Error!Box {161    return switch (value.kind) {162        .plain => layoutStack(arena, value),163        .overbrace => layoutBraceAnnotation(arena, value.base, .over),164        .underbrace => layoutBraceAnnotation(arena, value.base, .under),165        .boxed => layoutBoxed(arena, value.base),166    };167}168169const BraceSide = enum {170    over,171    under,172};173174fn layoutStack(arena: std.mem.Allocator, value: ast.Annotation) std.mem.Allocator.Error!Box {175    const base = try layout(arena, value.base);176    const over = if (value.over) |expr| try layout(arena, expr) else null;177    const under = if (value.under) |expr| try layout(arena, expr) else null;178    const width = @max(base.width, @max(if (over) |box| box.width else 0, if (under) |box| box.width else 0));179    const top = if (over) |box| box.height else 0;180    const bottom = if (under) |box| box.height else 0;181    var out = try makeBox(arena, width, top + base.height + bottom, top + base.baseline);182    if (over) |box| putBox(&out, centered(width, box.width), 0, box);183    putBox(&out, centered(width, base.width), top, base);184    if (under) |box| putBox(&out, centered(width, box.width), top + base.height, box);185    return out;186}187188fn layoutBraceAnnotation(arena: std.mem.Allocator, body_expr: *ast.Expr, side: BraceSide) std.mem.Allocator.Error!Box {189    const body = try layout(arena, body_expr);190    var out = try makeBox(arena, body.width, body.height + 1, switch (side) {191        .over => body.baseline + 1,192        .under => body.baseline,193    });194    if (body.width != 0) {195        switch (side) {196            .over => for (0..body.width) |x| out.set(x, 0, "⏞"),197            .under => for (0..body.width) |x| out.set(x, body.height, "⏟"),198        }199    }200    switch (side) {201        .over => putBox(&out, 0, 1, body),202        .under => putBox(&out, 0, 0, body),203    }204    return out;205}206207fn layoutBoxed(arena: std.mem.Allocator, body_expr: *ast.Expr) std.mem.Allocator.Error!Box {208    const body = try layout(arena, body_expr);209    var out = try makeBox(arena, body.width + 4, body.height + 2, body.baseline + 1);210    out.set(0, 0, "┌");211    for (1..out.width - 1) |x| out.set(x, 0, "─");212    out.set(out.width - 1, 0, "┐");213    for (1..out.height - 1) |y| {214        out.set(0, y, "│");215        out.set(out.width - 1, y, "│");216    }217    out.set(0, out.height - 1, "└");218    for (1..out.width - 1) |x| out.set(x, out.height - 1, "─");219    out.set(out.width - 1, out.height - 1, "┘");220    putBox(&out, 2, 1, body);221    return out;222}223224fn layoutDelimited(arena: std.mem.Allocator, value: ast.Delimited) std.mem.Allocator.Error!Box {225    const body = try layout(arena, value.body);226    const left = try layoutDelimiter(arena, value.left, body.height, body.baseline);227    const right = try layoutDelimiter(arena, value.right, body.height, body.baseline);228    var out = try makeBox(arena, left.width + body.width + right.width, body.height, body.baseline);229    putBox(&out, 0, 0, left);230    putBox(&out, left.width, 0, body);231    putBox(&out, left.width + body.width, 0, right);232    return out;233}234235fn layoutDelimiter(236    arena: std.mem.Allocator,237    delimiter: ast.Delimiter,238    height: usize,239    baseline: usize,240) std.mem.Allocator.Error!Box {241    return switch (delimiter) {242        .none => makeBox(arena, 0, height, baseline),243        .shape => |shape| block: {244            var out = try makeBox(arena, 1, height, baseline);245            for (0..height) |y| out.set(0, y, delimiterShapeGlyph(shape, y, height));246            break :block out;247        },248        .text => |value| block: {249            const text = try textBox(arena, value);250            var out = try makeBox(arena, text.width, height, baseline);251            putBox(&out, 0, @min(baseline, height - 1), text);252            break :block out;253        },254    };255}256257fn layoutGrid(arena: std.mem.Allocator, value: ast.Grid) std.mem.Allocator.Error!Box {258    if (value.rows.len == 0) return makeBox(arena, 0, 1, 0);259    var columns: usize = 0;260    for (value.rows) |row| columns = @max(columns, row.cells.len);261    if (columns == 0) return makeBox(arena, 0, 1, 0);262263    const column_widths = try arena.alloc(usize, columns);264    for (column_widths) |*width| width.* = 0;265    const row_baselines = try arena.alloc(usize, value.rows.len);266    const row_heights = try arena.alloc(usize, value.rows.len);267    const boxes = try arena.alloc([]Box, value.rows.len);268269    for (value.rows, 0..) |row, row_index| {270        boxes[row_index] = try arena.alloc(Box, row.cells.len);271        var baseline: usize = 0;272        var descent: usize = 0;273        for (row.cells, 0..) |cell, column_index| {274            const box = try layout(arena, cell);275            boxes[row_index][column_index] = box;276            column_widths[column_index] = @max(column_widths[column_index], box.width);277            baseline = @max(baseline, box.baseline);278            descent = @max(descent, box.height - box.baseline - 1);279        }280        row_baselines[row_index] = baseline;281        row_heights[row_index] = baseline + descent + 1;282    }283284    const gap: usize = if (columns > 1) 2 else 0;285    var body_width: usize = gap * (columns - 1);286    for (column_widths) |width| body_width += width;287    var body_height: usize = 0;288    for (row_heights) |height| body_height += height;289290    const left_width = if (leftFence(value.fence) != null) @as(usize, 1) else 0;291    const right_width = if (rightFence(value.fence) != null) @as(usize, 1) else 0;292    var out = try makeBox(arena, left_width + body_width + right_width, body_height, body_height / 2);293    if (leftFence(value.fence)) |fence| drawFence(&out, 0, fence, .left);294    if (rightFence(value.fence)) |fence| drawFence(&out, left_width + body_width, fence, .right);295296    var y: usize = 0;297    for (value.rows, 0..) |row, row_index| {298        var x = left_width;299        for (0..columns) |column_index| {300            if (column_index < row.cells.len) {301                const box = boxes[row_index][column_index];302                const offset = switch (value.alignment) {303                    .center => centered(column_widths[column_index], box.width),304                    .left => 0,305                };306                putBox(&out, x + offset, y + row_baselines[row_index] - box.baseline, box);307            }308            x += column_widths[column_index] + gap;309        }310        y += row_heights[row_index];311    }312    return out;313}314315pub fn spaceCells(value: ast.Space) usize {316    if (value.numerator <= 0) return 0;317    const numerator: u64 = @intCast(value.numerator);318    const denominator: u64 = value.denominator;319    const cells: usize = @intCast(@divTrunc(numerator * 2 + denominator - 1, denominator));320    return @max(@as(usize, 1), cells);321}322323fn textBox(arena: std.mem.Allocator, value: []const u8) std.mem.Allocator.Error!Box {324    var count: usize = 0;325    var index: usize = 0;326    while (index < value.len) {327        const len = std.unicode.utf8ByteSequenceLength(value[index]) catch 1;328        index += @min(len, value.len - index);329        count += 1;330    }331    var out = try makeBox(arena, count, 1, 0);332    index = 0;333    var x: usize = 0;334    while (index < value.len) : (x += 1) {335        const len = std.unicode.utf8ByteSequenceLength(value[index]) catch 1;336        const end = index + @min(len, value.len - index);337        out.set(x, 0, value[index..end]);338        index = end;339    }340    return out;341}342343fn makeBox(arena: std.mem.Allocator, width: usize, height: usize, baseline: usize) std.mem.Allocator.Error!Box {344    const cells = try arena.alloc(Cell, width * height);345    for (cells) |*cell| cell.* = space;346    return .{347        .width = width,348        .height = height,349        .baseline = baseline,350        .cells = cells,351    };352}353354fn putBox(out: *Box, x: usize, y: usize, child: Box) void {355    for (0..child.height) |row| {356        for (0..child.width) |col| {357            out.set(x + col, y + row, child.at(col, row));358        }359    }360}361362fn centered(width: usize, inner: usize) usize {363    if (inner >= width) return 0;364    return (width - inner) / 2;365}366367const Fence = enum {368    paren,369    bracket,370    brace,371    bar,372    double_bar,373};374375const FenceSide = enum {376    left,377    right,378};379380fn leftFence(fence: ast.GridFence) ?Fence {381    return switch (fence) {382        .none => null,383        .paren => .paren,384        .bracket => .bracket,385        .brace => .brace,386        .bar => .bar,387        .double_bar => .double_bar,388        .left_brace => .brace,389    };390}391392fn rightFence(fence: ast.GridFence) ?Fence {393    return switch (fence) {394        .none, .left_brace => null,395        .paren => .paren,396        .bracket => .bracket,397        .brace => .brace,398        .bar => .bar,399        .double_bar => .double_bar,400    };401}402403fn drawFence(out: *Box, x: usize, fence: Fence, side: FenceSide) void {404    for (0..out.height) |y| out.set(x, y, fenceGlyph(fence, side, y, out.height));405}406407fn delimiterShapeGlyph(shape: ast.DelimiterShape, y: usize, height: usize) []const u8 {408    return switch (shape) {409        .left_paren => fenceGlyph(.paren, .left, y, height),410        .right_paren => fenceGlyph(.paren, .right, y, height),411        .left_bracket => fenceGlyph(.bracket, .left, y, height),412        .right_bracket => fenceGlyph(.bracket, .right, y, height),413        .left_brace => fenceGlyph(.brace, .left, y, height),414        .right_brace => fenceGlyph(.brace, .right, y, height),415        .bar => "|",416        .double_bar => "‖",417        .left_angle => "⟨",418        .right_angle => "⟩",419        .left_double_angle => "⟪",420        .right_double_angle => "⟫",421        .left_double_bracket => "⟦",422        .right_double_bracket => "⟧",423        .left_floor => if (height == 1 or y + 1 == height) "⌊" else "⎢",424        .right_floor => if (height == 1 or y + 1 == height) "⌋" else "⎥",425        .left_ceil => if (height == 1 or y == 0) "⌈" else "⎢",426        .right_ceil => if (height == 1 or y == 0) "⌉" else "⎥",427    };428}429430fn fenceGlyph(fence: Fence, side: FenceSide, y: usize, height: usize) []const u8 {431    return switch (fence) {432        .bar => "|",433        .double_bar => "‖",434        .paren => if (height == 1)435            switch (side) {436                .left => "(",437                .right => ")",438            }439        else if (y == 0)440            switch (side) {441                .left => "⎛",442                .right => "⎞",443            }444        else if (y + 1 == height)445            switch (side) {446                .left => "⎝",447                .right => "⎠",448            }449        else switch (side) {450            .left => "⎜",451            .right => "⎟",452        },453        .bracket => if (height == 1)454            switch (side) {455                .left => "[",456                .right => "]",457            }458        else if (y == 0)459            switch (side) {460                .left => "⎡",461                .right => "⎤",462            }463        else if (y + 1 == height)464            switch (side) {465                .left => "⎣",466                .right => "⎦",467            }468        else switch (side) {469            .left => "⎢",470            .right => "⎥",471        },472        .brace => if (height == 1)473            switch (side) {474                .left => "{",475                .right => "}",476            }477        else if (y == 0)478            switch (side) {479                .left => "⎧",480                .right => "⎫",481            }482        else if (y + 1 == height)483            switch (side) {484                .left => "⎩",485                .right => "⎭",486            }487        else if (y == height / 2)488            switch (side) {489                .left => "⎨",490                .right => "⎬",491            }492        else switch (side) {493            .left => "⎪",494            .right => "⎪",495        },496    };497}

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