Allow passing allocator to parsers with withAllocatorParser()

Author: maxbol

.envrc

@@ -0,0 +1 @@
+use flake

.gitignore

@@ -1,2 +1,3 @@
 .zig-cache
 zig-out
+.direnv/

clap.zig

@@ -770,15 +770,16 @@ pub fn parseEx(
 
             const parser = comptime switch (param.takes_value) {
                 .none => null,
-                .one, .many => @field(value_parsers, param.id.value()),
+                .one, .many => withAllocatorParser(@field(value_parsers, param.id.value())),
             };
 
             const name = longest.name[0..longest.name.len].*;
+
             switch (param.takes_value) {
                 .none => @field(arguments, &name) +|= 1,
-                .one => @field(arguments, &name) = try parser(arg.value.?),
+                .one => @field(arguments, &name) = try parser(arg.value.?, allocator),
                 .many => {
-                    const value = try parser(arg.value.?);
+                    const value = try parser(arg.value.?, allocator);
                     try @field(arguments, &name).append(allocator, value);
                 },
             }
@@ -801,7 +802,7 @@ pub fn parseEx(
 
             const parser = comptime switch (param.takes_value) {
                 .none => null,
-                .one, .many => @field(value_parsers, param.id.value()),
+                .one, .many => withAllocatorParser(@field(value_parsers, param.id.value())),
             };
 
             // We keep track of how many positionals we have received. This is used to pick which
@@ -811,8 +812,8 @@ pub fn parseEx(
             const last = positionals.len == i + 1;
             if ((last and positional_count >= i) or positional_count == i) {
                 switch (@typeInfo(@TypeOf(pos.*))) {
-                    .optional => pos.* = try parser(arg.value.?),
-                    else => try pos.append(allocator, try parser(arg.value.?)),
+                    .optional => pos.* = try parser(arg.value.?, allocator),
+                    else => try pos.append(allocator, try parser(arg.value.?, allocator)),
                 }
 
                 if (opt.terminating_positional <= positional_count)
@@ -852,6 +853,44 @@ pub fn parseEx(
     };
 }
 
+fn AllocatorParserReturnType(parser: anytype) type {
+    const parser_info = switch (@typeInfo(@TypeOf(parser))) {
+        .@"fn" => |info| info,
+        else => {
+            return void;
+        },
+    };
+    return parser_info.return_type orelse void;
+}
+
+fn AllocatorParser(parser: anytype) type {
+    return fn (value: anytype, allocator: std.mem.Allocator) AllocatorParserReturnType(parser);
+}
+
+pub fn withAllocatorParser(parser: anytype) AllocatorParser(parser) {
+    const parser_info = switch (@typeInfo(@TypeOf(parser))) {
+        .@"fn" => |info| info,
+        else => {
+            @compileError("withAllocatorParser() must be called with a non-null parser implementation");
+        },
+    };
+    return struct {
+        pub fn parseWithAllocator(value: anytype, allocator: std.mem.Allocator) AllocatorParserReturnType(parser) {
+            switch (parser_info.params.len) {
+                2 => {
+                    return parser(value, allocator);
+                },
+                1 => {
+                    return parser(value);
+                },
+                else => {
+                    return error.InvalidArgumentParser;
+                },
+            }
+        }
+    }.parseWithAllocator;
+}
+
 /// The result of `parseEx`. Is owned by the caller and should be freed with `deinit`.
 pub fn ResultEx(
     comptime Id: type,

flake.lock

@@ -0,0 +1,97 @@
+{
+  description = "Utility to control Neovim colorscheme from the terminal";
+
+  inputs = {
+    zig2nix.url = "github:Cloudef/zig2nix";
+  };
+
+  outputs = {zig2nix, ...}: let
+    flake-utils = zig2nix.inputs.flake-utils;
+  in (flake-utils.lib.eachDefaultSystem (system: let
+    # Zig flake helper
+    # Check the flake.nix in zig2nix project for more options:
+    # <https://github.com/Cloudef/zig2nix/blob/master/flake.nix>
+    env = zig2nix.outputs.zig-env.${system} {};
+    system-triple = env.lib.zigTripleFromString system;
+  in
+    with builtins;
+    with env.lib;
+    with env.pkgs.lib; rec {
+      # nix build .#target.{zig-target}
+      # e.g. nix build .#target.x86_64-linux-gnu
+      packages.target = genAttrs allTargetTriples (target:
+        env.packageForTarget target ({
+            src = cleanSource ./.;
+
+            nativeBuildInputs = with env.pkgs; [];
+            buildInputs = with env.pkgsForTarget target; [];
+
+            # Smaller binaries and avoids shipping glibc.
+            zigPreferMusl = true;
+
+            # This disables LD_LIBRARY_PATH mangling, binary patching etc...
+            # The package won't be usable inside nix.
+            zigDisableWrap = true;
+
+            zigBuildFlags = ["-Doptimize=ReleaseFast"];
+
+            meta = {
+              description = "A simple and easy to use command line argument parser library for Zig.";
+              license = licenses.mit;
+              maintainers = with lib.maintainers; [];
+            };
+          }
+          // optionalAttrs (!pathExists ./build.zig.zon) {
+            pname = "my-zig-project";
+            version = "0.0.0";
+          }));
+
+      # nix build .
+      packages.default = packages.target.${system-triple}.override {
+        # Prefer nix friendly settings.
+        zigPreferMusl = false;
+        zigDisableWrap = false;
+      };
+
+      # For bundling with nix bundle for running outside of nix
+      # example: https://github.com/ralismark/nix-appimage
+      apps.bundle.target = genAttrs allTargetTriples (target: let
+        pkg = packages.target.${target};
+      in {
+        type = "app";
+        program = "${pkg}/bin/default";
+      });
+
+      # default bundle
+      apps.bundle.default = apps.bundle.target.${system-triple};
+
+      # nix run .
+      apps.default = env.app [] "zig build run -- \"$@\"";
+
+      # nix run .#build
+      apps.build = env.app [] "zig build \"$@\"";
+
+      # nix run .#test
+      apps.test = env.app [] "zig build test -- \"$@\"";
+
+      # nix run .#docs
+      apps.docs = env.app [] "zig build docs -- \"$@\"";
+
+      # nix run .#deps
+      apps.deps = env.showExternalDeps;
+
+      # nix run .#zon2json
+      apps.zon2json = env.app [env.zon2json] "zon2json \"$@\"";
+
+      # nix run .#zon2json-lock
+      apps.zon2json-lock = env.app [env.zon2json-lock] "zon2json-lock \"$@\"";
+
+      # nix run .#zon2nix
+      apps.zon2nix = env.app [env.zon2nix] "zon2nix \"$@\"";
+
+      # nix develop
+      devShells.default =
+        env.mkShell {
+        };
+    }));
+}