tiny.smg.tree.runtime.node

1const std = @import("std");2const runtime = @import("root.zig");34const abi = runtime.abi;5const subtree = runtime.subtree;67pub const Node = struct {8    tree: ?*const subtree.Tree,9    value: ?*const subtree.Subtree,10    alias_symbol: abi.Symbol = 0,1112    pub fn init(tree: *const subtree.Tree, value: *const subtree.Subtree) Node {13        return .{ .tree = tree, .value = value };14    }1516    pub fn empty() Node {17        return .{ .tree = null, .value = null };18    }19};2021pub fn kind(node: Node) []const u8 {22    const tree = node.tree orelse return "";23    const value = node.value orelse return "";24    const symbol = if (node.alias_symbol == 0) value.symbol else node.alias_symbol;25    return tree.language.symbolName(symbol);26}2728pub fn childCount(node: Node) u32 {29    return relevantCount(node, true);30}3132pub fn namedChildCount(node: Node) u32 {33    return relevantCount(node, false);34}3536pub fn child(node: Node, index: u32) Node {37    return childAt(node, index, true);38}3940pub fn namedChild(node: Node, index: u32) Node {41    return childAt(node, index, false);42}4344pub fn childByField(node: Node, comptime field: []const u8) ?Node {45    const tree = node.tree orelse return null;46    const field_id = tree.language.fieldId(field);47    if (field_id == 0) return null;48    return childByFieldId(node, field_id);49}5051pub fn fieldNameForChild(initial: Node, requested: u32) ?[]const u8 {52    var node = initial;53    var target = requested;54    var inherited: ?[]const u8 = null;55    while (true) {56        const tree = node.tree orelse return null;57        const value = node.value orelse return null;58        var visible_index: u32 = 0;59        var structural_index: u32 = 0;60        var descend: ?Node = null;61        for (value.children) |child_value| {62            const child_structural_index = structural_index;63            const alias_symbol = aliasFor(node, child_value, structural_index);64            if (!child_value.extra) structural_index += 1;65            const direct = Node{ .tree = tree, .value = child_value, .alias_symbol = alias_symbol };66            if (isRelevant(direct, true)) {67                if (visible_index == target) {68                    if (child_value.extra) return null;69                    return directFieldName(node, child_structural_index) orelse inherited;70                }71                visible_index += 1;72                continue;73            }74            const count = relevantCount(direct, true);75            if (target >= visible_index and target - visible_index < count) {76                if (!child_value.extra) inherited = directFieldName(node, child_structural_index) orelse inherited;77                target -= visible_index;78                descend = direct;79                break;80            }81            visible_index += count;82        }83        node = descend orelse return null;84    }85}8687pub fn isNamed(node: Node) bool {88    const tree = node.tree orelse return false;89    const value = node.value orelse return false;90    if (node.alias_symbol != 0) return tree.language.symbolMetadata(node.alias_symbol).named;91    return value.named;92}9394pub fn startLine(node: Node) i64 {95    const value = node.value orelse return 0;96    return @intCast(value.start.point.row + 1);97}9899pub fn endLine(node: Node) i64 {100    const value = node.value orelse return 0;101    return @intCast(value.end.point.row + 1);102}103104pub fn startByte(node: Node) u32 {105    return (node.value orelse return 0).start.byte;106}107108pub fn endByte(node: Node) u32 {109    return (node.value orelse return 0).end.byte;110}111112pub fn slice(source: []const u8, node: Node) []const u8 {113    const start = @min(@as(usize, startByte(node)), source.len);114    const end = @min(@as(usize, endByte(node)), source.len);115    return source[start..@max(start, end)];116}117118fn childByFieldId(initial: Node, field_id: abi.Field) ?Node {119    var node = initial;120    while (true) {121        const tree = node.tree orelse return null;122        const value = node.value orelse return null;123        if (value.children.len == 0) return null;124        const fields = tree.language.fieldMap(value.production_id);125        if (fields.len == 0) return null;126127        var start: usize = 0;128        while (start < fields.len and fields[start].field_id < field_id) : (start += 1) {}129        if (start == fields.len or fields[start].field_id != field_id) return null;130        var end = start + 1;131        while (end < fields.len and fields[end].field_id == field_id) : (end += 1) {}132133        var field_index = start;134        var structural_index: u32 = 0;135        var inherited: ?Node = null;136        for (value.children) |child_value| {137            const alias_symbol = aliasFor(node, child_value, structural_index);138            const direct = Node{ .tree = tree, .value = child_value, .alias_symbol = alias_symbol };139            if (child_value.extra) continue;140            const current_index = structural_index;141            structural_index += 1;142            if (current_index < fields[field_index].child_index) continue;143            if (current_index > fields[field_index].child_index) return null;144            if (fields[field_index].inherited) {145                if (field_index + 1 == end) {146                    inherited = direct;147                    break;148                }149                if (childByFieldId(direct, field_id)) |result| return result;150                field_index += 1;151                if (field_index == end) return null;152            } else if (isRelevant(direct, true)) {153                return direct;154            } else {155                const result = childAt(direct, 0, true);156                if (result.value != null) return result;157                field_index += 1;158                if (field_index == end) return null;159            }160        }161        node = inherited orelse return null;162    }163}164165fn childAt(initial: Node, requested: u32, include_anonymous: bool) Node {166    var node = initial;167    var target = requested;168    while (true) {169        const tree = node.tree orelse return Node.empty();170        const value = node.value orelse return Node.empty();171        var visible_index: u32 = 0;172        var structural_index: u32 = 0;173        var descend: ?Node = null;174        for (value.children) |child_value| {175            const alias_symbol = aliasFor(node, child_value, structural_index);176            if (!child_value.extra) structural_index += 1;177            const direct = Node{ .tree = tree, .value = child_value, .alias_symbol = alias_symbol };178            if (isRelevant(direct, include_anonymous)) {179                if (visible_index == target) return direct;180                visible_index += 1;181                continue;182            }183            const count = relevantCount(direct, include_anonymous);184            if (target >= visible_index and target - visible_index < count) {185                target -= visible_index;186                descend = direct;187                break;188            }189            visible_index += count;190        }191        node = descend orelse return Node.empty();192    }193}194195fn relevantCount(node: Node, include_anonymous: bool) u32 {196    const value = node.value orelse return 0;197    return if (include_anonymous) value.visible_descendant_count else value.named_descendant_count;198}199200fn isRelevant(node: Node, include_anonymous: bool) bool {201    const tree = node.tree orelse return false;202    const value = node.value orelse return false;203    if (node.alias_symbol != 0) {204        const metadata = tree.language.symbolMetadata(node.alias_symbol);205        return if (include_anonymous) metadata.visible else metadata.named;206    }207    return value.visible and (include_anonymous or value.named);208}209210fn aliasFor(parent: Node, child_value: *const subtree.Subtree, structural_index: u32) abi.Symbol {211    if (child_value.extra) return 0;212    const tree = parent.tree orelse return 0;213    const value = parent.value orelse return 0;214    const aliases = tree.language.aliases(value.production_id);215    if (structural_index >= aliases.len) return 0;216    return aliases[structural_index];217}218219fn directFieldName(parent: Node, structural_index: u32) ?[]const u8 {220    const tree = parent.tree orelse return null;221    const value = parent.value orelse return null;222    for (tree.language.fieldMap(value.production_id)) |field| {223        if (!field.inherited and field.child_index == structural_index) {224            const pointer = tree.language.raw.field_names.?[field.field_id];225            if (@intFromPtr(pointer) == 0) return null;226            return std.mem.span(@as([*:0]const u8, @ptrCast(pointer)));227        }228    }229    return null;230}

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