logging without logger, better public API

build.zig.zon

@@ -1,6 +1,6 @@
 .{
     .name = .faller,
-    .version = "0.2.1",
+    .version = "0.3.1",
     .minimum_zig_version = "0.15.1",
     .paths = .{
         "build.zig",

src/root.zig

@@ -1,3 +1,21 @@
+//! A tag based Logger. Example:
+//!
+//! ```zig
+//! log(.foo, "Anonymous log", .{});
+//!
+//! const module_log = scope(.module);
+//! module_log.log(.debug, "Hello {s}!", .{"World"});
+//!
+//! const sub_module_log = module_log.scope(.bar);
+//! sub_module_log.log(.perf, "Operation took {} ns", .{5});
+//! ```
+//!
+//! Output:
+//! ```
+//! foo: Anonymous log
+//! module|debug: Hello World!
+//! module|bar|perf: Operation took 5 ns
+//! ```
 const std = @import("std");
 const root = @import("root");
 const builtin = @import("builtin");
@@ -20,51 +38,86 @@ pub const Options = struct {
     /// tags is present it **isn't** logged. May overwrite `tags_enabled`.
     tags_disabled: []const @Type(.enum_literal) = &.{},
     buffer_size: u64 = 64,
-    disabled_in_test: bool = true,
+    disabled_in_test: bool = false,
 };
 
-pub const empty_logger = Logger{ .base_tags = &.{} };
+/// A Logger with prefixes.
+pub const Logger = struct {
+    base_tags: []const @Type(.enum_literal),
 
-/// A tag based Logger. Examples:
-///
-/// ```zig
-/// pub const module_log = Logger{ .base_tags = &.{.module} };
-/// module_log.log(.debug, "Hello {s}!", .{"World"});
-///
-/// pub const sub_module_log = module_log.scope(.bar);
-/// sub_module_log.log(.perf, "Operation took {} ns", .{time_ns});
-/// ```
-pub const Logger = @This();
+    /// Creates a new logger with an additional tag prefix.
+    pub fn scope(comptime logger: Logger, comptime tag: @Type(.enum_literal)) Logger {
+        return .{
+            .base_tags = logger.base_tags ++ [_]@Type(.enum_literal){tag},
+        };
+    }
 
-base_tags: []const @Type(.enum_literal),
+    /// Log with one additional `tag`. Checks whether the log is enabled.
+    pub fn log(
+        comptime logger: Logger,
+        comptime tag: @Type(.enum_literal),
+        comptime format: []const u8,
+        args: anytype,
+    ) void {
+        logger.logTags(&.{tag}, format, args);
+    }
 
-/// Creates a new logger with an extended tag prefix.
-pub fn scope(comptime logger: Logger, comptime tag: @TypeOf(.enum_literal)) Logger {
+    /// Log with multiple `tags`. Checks whether the log is enabled.
+    pub fn logTags(
+        comptime logger: Logger,
+        comptime tags: []const @Type(.enum_literal),
+        comptime format: []const u8,
+        args: anytype,
+    ) void {
+        if (builtin.is_test and options.disabled_in_test) return;
+        const all_tags = logger.base_tags ++ tags;
+        options.function(all_tags, format, args);
+    }
+};
+
+/// Creates a new logger with a tag prefix.
+pub fn scope(comptime tag: @TypeOf(.enum_literal)) Logger {
     return .{
-        .base_tags = logger.base_tags ++ [_]@Type(.enum_literal){tag},
+        .base_tags = &[_]@Type(.enum_literal){tag},
     };
 }
 
 /// Log with one `tag`. Checks whether the log is enabled.
 pub fn log(
-    comptime logger: Logger,
     comptime tag: @Type(.enum_literal),
     comptime format: []const u8,
     args: anytype,
 ) void {
-    logger.logTags(&.{tag}, format, args);
+    logTags(&.{tag}, format, args);
 }
 
 /// Log with multiple `tags`. Checks whether the log is enabled.
 pub fn logTags(
-    comptime logger: Logger,
     comptime tags: []const @Type(.enum_literal),
     comptime format: []const u8,
     args: anytype,
 ) void {
     if (builtin.is_test and options.disabled_in_test) return;
-    const all_tags = comptime logger.base_tags ++ tags;
-    options.function(all_tags, format, args);
+    options.function(tags, format, args);
+}
+
+/// Checks whether the log is enabled for a specific combination of `tags`. Depends on the `options`
+/// set.
+pub fn logEnabled(comptime tags: []const @Type(.enum_literal)) bool {
+    // If `tags` has at least one in `options.tags_disabled` then we never log.
+    if (options.tags_disabled.len > 0) {
+        if (intersect(tags, options.tags_disabled)) {
+            return false;
+        }
+    }
+
+    // If `tags` has at least one in `options.tags_enabled` then we should log.
+    if (options.tags_enabled.len > 0) {
+        return intersect(tags, options.tags_enabled);
+    }
+
+    // If neither is set then we just log everything.
+    return true;
 }
 
 /// Return `false` if `as` and `bs` have no common member. Else return `true`.
@@ -79,25 +132,6 @@ fn intersect(comptime as: []const @Type(.enum_literal), comptime bs: []const @Ty
     return false;
 }
 
-/// Checks whether the log is enabled for a specific combination of `tags`. Depends on the `options`
-/// set.
-pub fn logEnabled(comptime tags: []const @Type(.enum_literal)) bool {
-    // If `tags` has at least one in `options.tags_disabled` then we never log.
-    if (options.tags_disabled.len > 0) {
-        if (comptime intersect(tags, options.tags_disabled)) {
-            return false;
-        }
-    }
-
-    // If `tags` has at least one in `options.tags_enabled` then we should log.
-    if (options.tags_enabled.len > 0) {
-        return comptime intersect(tags, options.tags_enabled);
-    }
-
-    // If neither is set then we just log everything.
-    return true;
-}
-
 fn defaultLogFunction(
     comptime tags: []const @Type(.enum_literal),
     comptime format: []const u8,
@@ -117,3 +151,13 @@ fn defaultLogFunction(
     defer std.debug.unlockStderrWriter();
     nosuspend stderr.print(prefix ++ ": " ++ format ++ "\n", args) catch return;
 }
+
+test {
+    log(.foo, "Anonymous log", .{});
+
+    const module_log = scope(.module);
+    module_log.log(.debug, "Hello {s}!", .{"World"});
+
+    const sub_module_log = module_log.scope(.bar);
+    sub_module_log.log(.perf, "Operation took {} ns", .{5});
+}