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std: expose fmt methods and structs for parsing
This commit is contained in:
Tristan Ross
Veikka Tuominen
parent
6f3dacc107
commit
de6cafa80f
170
lib/std/fmt.zig
170
lib/std/fmt.zig
@ -148,7 +148,7 @@ pub fn format(
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comptime assert(fmt[i] == '}');
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i += 1;
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const placeholder = comptime parsePlaceholder(fmt[fmt_begin..fmt_end].*);
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const placeholder = comptime Placeholder.parse(fmt[fmt_begin..fmt_end].*);
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const arg_pos = comptime switch (placeholder.arg) {
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.none => null,
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.number => |pos| pos,
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@ -205,102 +205,102 @@ pub fn format(
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}
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}
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fn parsePlaceholder(comptime str: anytype) Placeholder {
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comptime var parser = Parser{ .buf = &str };
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// Parse the positional argument number
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const arg = comptime parser.specifier() catch |err|
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@compileError(@errorName(err));
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// Parse the format specifier
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const specifier_arg = comptime parser.until(':');
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// Skip the colon, if present
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if (comptime parser.char()) |ch| {
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if (ch != ':') {
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@compileError("expected : or }, found '" ++ [1]u8{ch} ++ "'");
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}
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}
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// Parse the fill character
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// The fill parameter requires the alignment parameter to be specified
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// too
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const fill = comptime if (parser.peek(1)) |ch|
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switch (ch) {
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'<', '^', '>' => parser.char().?,
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else => ' ',
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}
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else
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' ';
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// Parse the alignment parameter
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const alignment: Alignment = comptime if (parser.peek(0)) |ch| init: {
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switch (ch) {
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'<', '^', '>' => _ = parser.char(),
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else => {},
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}
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break :init switch (ch) {
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'<' => .Left,
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'^' => .Center,
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else => .Right,
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};
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} else .Right;
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// Parse the width parameter
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const width = comptime parser.specifier() catch |err|
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@compileError(@errorName(err));
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// Skip the dot, if present
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if (comptime parser.char()) |ch| {
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if (ch != '.') {
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@compileError("expected . or }, found '" ++ [1]u8{ch} ++ "'");
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}
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}
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// Parse the precision parameter
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const precision = comptime parser.specifier() catch |err|
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@compileError(@errorName(err));
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if (comptime parser.char()) |ch| {
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@compileError("extraneous trailing character '" ++ [1]u8{ch} ++ "'");
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}
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return Placeholder{
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.specifier_arg = cacheString(specifier_arg[0..specifier_arg.len].*),
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.fill = fill,
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.alignment = alignment,
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.arg = arg,
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.width = width,
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.precision = precision,
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};
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}
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fn cacheString(str: anytype) []const u8 {
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return &str;
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}
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const Placeholder = struct {
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pub const Placeholder = struct {
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specifier_arg: []const u8,
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fill: u8,
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alignment: Alignment,
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arg: Specifier,
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width: Specifier,
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precision: Specifier,
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pub fn parse(comptime str: anytype) Placeholder {
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comptime var parser = Parser{ .buf = &str };
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// Parse the positional argument number
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const arg = comptime parser.specifier() catch |err|
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@compileError(@errorName(err));
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// Parse the format specifier
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const specifier_arg = comptime parser.until(':');
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// Skip the colon, if present
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if (comptime parser.char()) |ch| {
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if (ch != ':') {
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@compileError("expected : or }, found '" ++ [1]u8{ch} ++ "'");
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}
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}
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// Parse the fill character
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// The fill parameter requires the alignment parameter to be specified
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// too
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const fill = comptime if (parser.peek(1)) |ch|
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switch (ch) {
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'<', '^', '>' => parser.char().?,
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else => ' ',
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}
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else
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' ';
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// Parse the alignment parameter
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const alignment: Alignment = comptime if (parser.peek(0)) |ch| init: {
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switch (ch) {
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'<', '^', '>' => _ = parser.char(),
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else => {},
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}
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break :init switch (ch) {
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'<' => .Left,
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'^' => .Center,
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else => .Right,
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};
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} else .Right;
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// Parse the width parameter
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const width = comptime parser.specifier() catch |err|
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@compileError(@errorName(err));
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// Skip the dot, if present
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if (comptime parser.char()) |ch| {
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if (ch != '.') {
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@compileError("expected . or }, found '" ++ [1]u8{ch} ++ "'");
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}
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}
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// Parse the precision parameter
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const precision = comptime parser.specifier() catch |err|
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@compileError(@errorName(err));
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if (comptime parser.char()) |ch| {
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@compileError("extraneous trailing character '" ++ [1]u8{ch} ++ "'");
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}
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return Placeholder{
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.specifier_arg = cacheString(specifier_arg[0..specifier_arg.len].*),
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.fill = fill,
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.alignment = alignment,
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.arg = arg,
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.width = width,
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.precision = precision,
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};
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}
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};
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const Specifier = union(enum) {
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pub const Specifier = union(enum) {
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none,
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number: usize,
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named: []const u8,
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};
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const Parser = struct {
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pub const Parser = struct {
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buf: []const u8,
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pos: usize = 0,
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// Returns a decimal number or null if the current character is not a
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// digit
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fn number(self: *@This()) ?usize {
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pub fn number(self: *@This()) ?usize {
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var r: ?usize = null;
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while (self.pos < self.buf.len) : (self.pos += 1) {
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@ -319,7 +319,7 @@ const Parser = struct {
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// Returns a substring of the input starting from the current position
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// and ending where `ch` is found or until the end if not found
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fn until(self: *@This(), ch: u8) []const u8 {
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pub fn until(self: *@This(), ch: u8) []const u8 {
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const start = self.pos;
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if (start >= self.buf.len)
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@ -332,7 +332,7 @@ const Parser = struct {
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}
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// Returns one character, if available
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fn char(self: *@This()) ?u8 {
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pub fn char(self: *@This()) ?u8 {
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if (self.pos < self.buf.len) {
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const ch = self.buf[self.pos];
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self.pos += 1;
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@ -341,7 +341,7 @@ const Parser = struct {
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return null;
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}
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fn maybe(self: *@This(), val: u8) bool {
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pub fn maybe(self: *@This(), val: u8) bool {
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if (self.pos < self.buf.len and self.buf[self.pos] == val) {
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self.pos += 1;
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return true;
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@ -351,7 +351,7 @@ const Parser = struct {
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// Returns a decimal number or null if the current character is not a
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// digit
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fn specifier(self: *@This()) !Specifier {
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pub fn specifier(self: *@This()) !Specifier {
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if (self.maybe('[')) {
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const arg_name = self.until(']');
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@ -367,24 +367,24 @@ const Parser = struct {
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}
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// Returns the n-th next character or null if that's past the end
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fn peek(self: *@This(), n: usize) ?u8 {
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pub fn peek(self: *@This(), n: usize) ?u8 {
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return if (self.pos + n < self.buf.len) self.buf[self.pos + n] else null;
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}
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};
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const ArgSetType = u32;
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pub const ArgSetType = u32;
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const max_format_args = @typeInfo(ArgSetType).Int.bits;
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const ArgState = struct {
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pub const ArgState = struct {
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next_arg: usize = 0,
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used_args: ArgSetType = 0,
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args_len: usize,
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fn hasUnusedArgs(self: *@This()) bool {
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pub fn hasUnusedArgs(self: *@This()) bool {
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return @popCount(self.used_args) != self.args_len;
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}
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fn nextArg(self: *@This(), arg_index: ?usize) ?usize {
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pub fn nextArg(self: *@This(), arg_index: ?usize) ?usize {
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const next_index = arg_index orelse init: {
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const arg = self.next_arg;
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self.next_arg += 1;
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@ -430,7 +430,7 @@ pub fn formatAddress(value: anytype, options: FormatOptions, writer: anytype) @T
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// This ANY const is a workaround for: https://github.com/ziglang/zig/issues/7948
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const ANY = "any";
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fn defaultSpec(comptime T: type) [:0]const u8 {
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pub fn defaultSpec(comptime T: type) [:0]const u8 {
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switch (@typeInfo(T)) {
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.Array => |_| return ANY,
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.Pointer => |ptr_info| switch (ptr_info.size) {
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