Add piping, Add type builtin, Add command -v builtin

src/builtin/builtin.zig

@@ -1,25 +1,24 @@
 const std = @import("std");
 
 const parser = @import("../shell/parser.zig");
-
-const cd = @import("cmds/cd.zig");
-const echo = @import("cmds/echo.zig");
-const exit = @import("cmds/exit.zig");
-const pwd = @import("cmds/pwd.zig");
-const run = @import("cmds/run.zig");
-
 const types = @import("types.zig");
 
-const CommandFn = *const fn (types.BuiltinCommandContext) anyerror!void;
+const CommandFn = *const fn (types.CommandContext) anyerror!void;
 
 const commands = std.StaticStringMap(CommandFn).initComptime(.{
-    .{ "cd", cd.execute },
-    .{ "pwd", pwd.execute },
-    .{ "run", run.execute },
-    .{ "echo", echo.execute },
-    .{ "exit", exit.execute },
+    .{ "cd", @import("cmds/cd.zig").execute },
+    .{ "pwd", @import("cmds/pwd.zig").execute },
+    .{ "type", @import("cmds/type.zig").execute },
+    .{ "command", @import("cmds/command.zig").execute },
+    .{ "run", @import("cmds/run.zig").execute },
+    .{ "echo", @import("cmds/echo.zig").execute },
+    .{ "exit", @import("cmds/exit.zig").execute },
 });
 
+pub fn find(name: []const u8) ?CommandFn {
+    return commands.get(name);
+}
+
 pub fn execute(
     io: std.Io,
     allocator: std.mem.Allocator,
@@ -29,9 +28,7 @@ pub fn execute(
     if (command.argv.len == 0)
         return true;
 
-    const name = command.argv[0];
-
-    const execute_fn = commands.get(name) orelse
+    const execute_fn = commands.get(command.argv[0]) orelse
         return false;
 
     try execute_fn(.{
@@ -39,6 +36,10 @@ pub fn execute(
         .allocator = allocator,
         .shell = shell,
         .argv = command.argv,
+
+        .stdin = std.Io.File.stdin(),
+        .stdout = std.Io.File.stdout(),
+        .stderr = std.Io.File.stderr(),
     });
 
     return true;

src/builtin/cmds/cd.zig

@@ -2,7 +2,7 @@ const std = @import("std");
 
 const types = @import("../types.zig");
 
-pub fn execute(ctx: types.BuiltinCommandContext) !void {
+pub fn execute(ctx: types.CommandContext) !void {
     const path = if (ctx.argv.len >= 2)
         ctx.argv[1]
     else

src/builtin/cmds/command.zig

@@ -0,0 +1,39 @@
+const std = @import("std");
+
+const resolver = @import("../resolver.zig");
+const types = @import("../types.zig");
+
+pub fn execute(ctx: types.CommandContext) !void {
+    if (ctx.argv.len < 2)
+        return;
+
+    if (!std.mem.eql(u8, ctx.argv[1], "-v"))
+        return;
+
+    if (ctx.argv.len < 3) {
+        std.debug.print("xsh: command: -v: missing command name\n", .{});
+        return;
+    }
+
+    const name = ctx.argv[2];
+
+    const result = try resolver.resolve(ctx, name) orelse {
+        return;
+    };
+
+    switch (result) {
+        .builtin => {
+            std.debug.print("{s}\n", .{name});
+        },
+
+        .alias => |value| {
+            std.debug.print("{s}\n", .{value});
+        },
+
+        .executable => |path| {
+            defer ctx.allocator.free(path);
+
+            std.debug.print("{s}\n", .{path});
+        },
+    }
+}

src/builtin/cmds/echo.zig

@@ -2,14 +2,14 @@ const std = @import("std");
 
 const types = @import("../types.zig");
 
-pub fn execute(ctx: types.BuiltinCommandContext) !void {
+pub fn execute(ctx: types.CommandContext) !void {
     for (ctx.argv[1..], 0..) |argument, index| {
         if (index != 0) {
-            try std.Io.File.stdout().writeStreamingAll(ctx.io, " ");
+            try ctx.stdout.writeStreamingAll(ctx.io, " ");
         }
 
-        try std.Io.File.stdout().writeStreamingAll(ctx.io, argument);
+        try ctx.stdout.writeStreamingAll(ctx.io, argument);
     }
 
-    try std.Io.File.stdout().writeStreamingAll(ctx.io, "\n");
+    try ctx.stdout.writeStreamingAll(ctx.io, "\n");
 }

src/builtin/cmds/exit.zig

@@ -1,5 +1,5 @@
 const types = @import("../types.zig");
 
-pub fn execute(ctx: types.BuiltinCommandContext) !void {
+pub fn execute(ctx: types.CommandContext) !void {
     ctx.shell.running = false;
 }

src/builtin/cmds/pwd.zig

@@ -2,10 +2,10 @@ const std = @import("std");
 
 const types = @import("../types.zig");
 
-pub fn execute(ctx: types.BuiltinCommandContext) !void {
+pub fn execute(ctx: types.CommandContext) !void {
     const path = try std.process.currentPathAlloc(ctx.io, ctx.allocator);
     defer ctx.allocator.free(path);
 
-    try std.Io.File.stdout().writeStreamingAll(ctx.io, path);
-    try std.Io.File.stdout().writeStreamingAll(ctx.io, "\n");
+    try ctx.stdout.writeStreamingAll(ctx.io, path);
+    try ctx.stdout.writeStreamingAll(ctx.io, "\n");
 }

src/builtin/cmds/run.zig

@@ -4,7 +4,7 @@ const script = @import("../../script/script.zig");
 
 const types = @import("../types.zig");
 
-pub fn execute(ctx: types.BuiltinCommandContext) !void {
+pub fn execute(ctx: types.CommandContext) !void {
     if (ctx.argv.len < 2) {
         std.debug.print("xsh: run: missing script path\n", .{});
         return;

src/builtin/cmds/type.zig

@@ -0,0 +1,48 @@
+const std = @import("std");
+
+const resolver = @import("../resolver.zig");
+const types = @import("../types.zig");
+
+pub fn execute(ctx: types.CommandContext) !void {
+    if (ctx.argv.len < 2) {
+        std.debug.print("xsh: type: missing command name\n", .{});
+        return;
+    }
+
+    if (ctx.argv.len > 2) {
+        std.debug.print("xsh: type: too many arguments\n", .{});
+        return;
+    }
+
+    const name = ctx.argv[1];
+
+    const result = try resolver.resolve(
+        ctx,
+        name,
+    ) orelse {
+        std.debug.print("xsh: type: {s}: not found\n", .{name});
+        return;
+    };
+
+    switch (result) {
+        .builtin => {
+            std.debug.print("{s} is a shell builtin\n", .{name});
+        },
+
+        .alias => |value| {
+            std.debug.print(
+                "{s} is aliased to '{s}'\n",
+                .{ name, value },
+            );
+        },
+
+        .executable => |path| {
+            defer ctx.allocator.free(path);
+
+            std.debug.print(
+                "{s} is {s}\n",
+                .{ name, path },
+            );
+        },
+    }
+}

src/builtin/resolver.zig

@@ -0,0 +1,101 @@
+const std = @import("std");
+
+const builtin = @import("builtin.zig");
+const types = @import("types.zig");
+
+pub fn resolve(
+    ctx: types.CommandContext,
+    name: []const u8,
+) !?types.ResolvedCommand {
+    if (builtin.find(name) != null)
+        return .builtin;
+
+    if (std.mem.indexOfAny(u8, name, "/\\") != null)
+        return .{
+            .executable = try ctx.allocator.dupe(u8, name),
+        };
+
+    const path = ctx.shell.environ.get("PATH") orelse
+        return null;
+
+    if (@import("builtin").os.tag == .windows) {
+        const pathext = ctx.shell.environ.get("PATHEXT") orelse
+            ".COM;.EXE;.BAT;.CMD";
+
+        var dirs = std.mem.splitScalar(u8, path, ';');
+
+        while (dirs.next()) |dir| {
+            if (dir.len == 0)
+                continue;
+
+            // Try the exact name first.
+            {
+                const candidate = try std.fs.path.join(
+                    ctx.allocator,
+                    &.{ dir, name },
+                );
+
+                if (std.Io.Dir.accessAbsolute(
+                    ctx.io,
+                    candidate,
+                    .{},
+                )) {
+                    return .{ .executable = candidate };
+                } else |_| {
+                    ctx.allocator.free(candidate);
+                }
+            }
+
+            // Then try PATHEXT.
+            var extensions = std.mem.splitScalar(u8, pathext, ';');
+
+            while (extensions.next()) |ext| {
+                const candidate_name = try std.fmt.allocPrint(
+                    ctx.allocator,
+                    "{s}{s}",
+                    .{ name, ext },
+                );
+                defer ctx.allocator.free(candidate_name);
+
+                const candidate = try std.fs.path.join(
+                    ctx.allocator,
+                    &.{ dir, candidate_name },
+                );
+
+                if (std.Io.Dir.accessAbsolute(
+                    ctx.io,
+                    candidate,
+                    .{},
+                )) {
+                    return .{ .executable = candidate };
+                } else |_| {
+                    ctx.allocator.free(candidate);
+                }
+            }
+        }
+    } else {
+        var dirs = std.mem.splitScalar(u8, path, ':');
+
+        while (dirs.next()) |dir| {
+            if (dir.len == 0)
+                continue;
+
+            const candidate = try std.fs.path.join(
+                ctx.allocator,
+                &.{ dir, name },
+            );
+
+            if (std.Io.Dir.accessAbsolute(
+                ctx.io,
+                candidate,
+                .{},
+            )) {
+                return .{ .executable = candidate };
+            } else |_| {
+                ctx.allocator.free(candidate);
+            }
+        }
+    }
+
+    return null;
+}

src/builtin/types.zig

@@ -6,9 +6,27 @@ pub const Shell = struct {
     environ: *const std.process.Environ.Map,
 };
 
-pub const BuiltinCommandContext = struct {
+pub const CommandContext = struct {
     io: std.Io,
     allocator: std.mem.Allocator,
     shell: *Shell,
     argv: []const []const u8,
+
+    stdin: std.Io.File,
+    stdout: std.Io.File,
+    stderr: std.Io.File,
+};
+
+pub const ResolvedCommand = union(enum) {
+    builtin,
+    alias: []const u8,
+    executable: []const u8,
+};
+
+pub const Command = struct {
+    argv: []const []const u8,
+};
+
+pub const Pipeline = struct {
+    commands: []const Command,
 };

src/main.zig

@@ -56,15 +56,20 @@ pub fn main(init: std.process.Init) !void {
     }
 }
 
-fn runPipeline(allocator: std.mem.Allocator, io: std.Io, shell: *builtin_types.Shell, source: []const u8) !void {
+fn runPipeline(
+    allocator: std.mem.Allocator,
+    io: std.Io,
+    shell: *builtin_types.Shell,
+    source: []const u8,
+) !void {
     const tokens = try lexer.lex(allocator, source);
-    const command = try parser.parse(allocator, tokens.items);
+    const pipeline = try parser.parse(allocator, tokens.items);
 
     try execute.run(
         io,
         allocator,
         shell,
-        command,
+        pipeline,
     );
 }
 

src/shell/execute.zig

@@ -9,17 +9,90 @@ pub fn run(
     io: std.Io,
     allocator: std.mem.Allocator,
     shell: *builtin_types.Shell,
-    command: parser.Command,
+    pipeline: parser.Pipeline,
 ) !void {
-    if (try builtin.execute(io, allocator, shell, command))
+    if (pipeline.commands.len == 0)
         return;
 
-    var child = try std.process.spawn(
-        io,
-        .{
-            .argv = command.argv,
-        },
-    );
+    if (pipeline.commands.len == 1) {
+        const command = pipeline.commands[0];
 
-    _ = try child.wait(io);
+        if (try builtin.execute(
+            io,
+            allocator,
+            shell,
+            command,
+        ))
+            return;
+
+        var child = try std.process.spawn(io, .{
+            .argv = command.argv,
+        });
+
+        _ = try child.wait(io);
+        return;
+    }
+
+    if (pipeline.commands.len != 2)
+        return error.UnsupportedPipeline;
+
+    const left = pipeline.commands[0];
+    const right = pipeline.commands[1];
+
+    var left_child = try std.process.spawn(io, .{
+        .argv = left.argv,
+        .stdout = .pipe,
+    });
+    defer {
+        if (left_child.stdout) |stdout|
+            stdout.close(io);
+    }
+
+    var right_child = try std.process.spawn(io, .{
+        .argv = right.argv,
+        .stdin = .pipe,
+    });
+    defer {
+        if (right_child.stdin) |stdin|
+            stdin.close(io);
+    }
+
+    const left_stdout = left_child.stdout orelse
+        return error.MissingPipe;
+
+    const right_stdin = right_child.stdin orelse
+        return error.MissingPipe;
+
+    var buffer: [4096]u8 = undefined;
+
+    var buffers = [_][]u8{
+        &buffer,
+    };
+
+    while (true) {
+        const n = left_stdout.readStreaming(
+            io,
+            &buffers,
+        ) catch |err| switch (err) {
+            error.EndOfStream => break,
+            else => return err,
+        };
+
+        if (n == 0)
+            break;
+
+        try right_stdin.writeStreamingAll(
+            io,
+            buffer[0..n],
+        );
+    }
+
+    right_stdin.close(io);
+    right_child.stdin = null;
+
+    left_stdout.close(io);
+    left_child.stdout = null;
+
+    _ = try left_child.wait(io);
+    _ = try right_child.wait(io);
 }

src/shell/lexer.zig

@@ -9,18 +9,69 @@ pub fn lex(
     source: []const u8,
 ) !std.ArrayList(Token) {
     var tokens: std.ArrayList(Token) = .empty;
+    var current: std.ArrayList(u8) = .empty;
 
-    var iterator = std.mem.tokenizeAny(
-        u8,
-        source,
-        " \t\r\n",
-    );
+    var quote: ?u8 = null;
 
-    while (iterator.next()) |word| {
+    for (source) |char| {
+        if (quote) |q| {
+            if (char == q) {
+                quote = null;
+            } else {
+                try current.append(allocator, char);
+            }
+
+            continue;
+        }
+
+        switch (char) {
+            '\'', '"' => {
+                quote = char;
+            },
+
+            ' ', '\t', '\r', '\n' => {
+                if (current.items.len != 0) {
+                    try tokens.append(
+                        allocator,
+                        .{
+                            .text = try current.toOwnedSlice(allocator),
+                        },
+                    );
+                }
+            },
+
+            '|' => {
+                if (current.items.len != 0) {
+                    try tokens.append(
+                        allocator,
+                        .{
+                            .text = try current.toOwnedSlice(allocator),
+                        },
+                    );
+                }
+
+                try tokens.append(
+                    allocator,
+                    .{
+                        .text = "|",
+                    },
+                );
+            },
+
+            else => {
+                try current.append(allocator, char);
+            },
+        }
+    }
+
+    if (quote != null)
+        return error.UnterminatedQuote;
+
+    if (current.items.len != 0) {
         try tokens.append(
             allocator,
             .{
-                .text = word,
+                .text = try current.toOwnedSlice(allocator),
             },
         );
     }

src/shell/parser.zig

@@ -6,24 +6,53 @@ pub const Command = struct {
     argv: []const []const u8,
 };
 
+pub const Pipeline = struct {
+    commands: []const Command,
+};
+
 pub fn parse(
     allocator: std.mem.Allocator,
     tokens: []const lexer.Token,
-) !Command {
-    if (tokens.len == 0) {
+) !Pipeline {
+    if (tokens.len == 0)
         return error.EmptyCommand;
+
+    var commands: std.ArrayList(Command) = .empty;
+    var argv: std.ArrayList([]const u8) = .empty;
+
+    for (tokens) |token| {
+        if (std.mem.eql(u8, token.text, "|")) {
+            if (argv.items.len == 0)
+                return error.EmptyCommand;
+
+            try commands.append(
+                allocator,
+                .{
+                    .argv = try argv.toOwnedSlice(allocator),
+                },
+            );
+
+            argv = .empty;
+            continue;
+        }
+
+        try argv.append(
+            allocator,
+            token.text,
+        );
     }
 
-    const argv = try allocator.alloc(
-        []const u8,
-        tokens.len,
+    if (argv.items.len == 0)
+        return error.EmptyCommand;
+
+    try commands.append(
+        allocator,
+        .{
+            .argv = try argv.toOwnedSlice(allocator),
+        },
     );
 
-    for (tokens, 0..) |token, index| {
-        argv[index] = token.text;
-    }
-
     return .{
-        .argv = argv,
+        .commands = try commands.toOwnedSlice(allocator),
     };
 }