refactor: eliminate duplicate enum variant spec

Modify the `str_enum!` macro to be able to handle multiple strings per
enum variant. This means that no separate step is required for defining
the enum. Instead definition of the enum and implementation of the
string conversion functions is now combined into a single macro
invocation, eliminating code duplication, as well as making it easier to
add and identify aliases for an enum variant.

Closes #12101

src/builtins/status.rs

@@ -14,23 +14,37 @@
 use libc::F_OK;
 use rust_embed::RustEmbed;
 
+/// Create an enum with name `$name`.
+/// Its variants are given as comma-separated tuples, with each tuple containing the variant name,
+/// as well as a string representations of the variant.
+/// Optionally, additional strings can be provided, which are considered aliases for the enum
+/// variant.
+/// The generated enum will implement a `from_str` function, mapping from `&str` to the associated
+/// enum variant if any, and `to_wstr`, which maps from a variant to the associated
+/// `$default_name`.
+/// It is the user's responsibility to ensure than none of the string arguments appears more than
+/// once.
 macro_rules! str_enum {
-    ($name:ident, $(($val:ident, $str:expr)),* $(,)?) => {
+    ($name:ident, $(($val:ident, $default_name:expr $(, $alias:expr)* $(,)?)),* $(,)?) => {
+        #[derive(Clone, Copy)]
+        enum $name {
+            $($val),*,
+        }
+
         impl $name {
-            fn from_wstr(s: &str) -> Option<Self> {
+            fn from_str(s: &str) -> Option<Self> {
                 // matching on str's lets us avoid having to do binary search and friends ourselves,
-                // this is ascii only anyways
+                // this is ASCII only anyways
                 match s {
-                    $($str => Some(Self::$val)),*,
+                    $($default_name => Some(Self::$val)),*,
+                    $($($alias => Some(Self::$val),)*)*
                     _ => None,
                 }
             }
 
             fn to_wstr(self) -> &'static wstr {
-                // There can be multiple vals => str mappings, and that's okay
-                #[allow(unreachable_patterns)]
                 match self {
-                    $(Self::$val => L!($str)),*,
+                    $(Self::$val => L!($default_name)),*,
                 }
             }
         }
@@ -38,53 +52,17 @@ fn to_wstr(self) -> &'static wstr {
 }
 
 use StatusCmd::*;
-#[derive(Clone, Copy)]
-enum StatusCmd {
-    STATUS_BASENAME,
-    STATUS_BUILD_INFO,
-    STATUS_CURRENT_CMD,
-    STATUS_CURRENT_COMMANDLINE,
-    STATUS_DIRNAME,
-    STATUS_FEATURES,
-    STATUS_FILENAME,
-    STATUS_FISH_PATH,
-    STATUS_FUNCTION,
-    STATUS_GET_FILE,
-    STATUS_IS_BLOCK,
-    STATUS_IS_BREAKPOINT,
-    STATUS_IS_COMMAND_SUB,
-    STATUS_IS_FULL_JOB_CTRL,
-    STATUS_IS_INTERACTIVE,
-    STATUS_IS_INTERACTIVE_JOB_CTRL,
-    STATUS_IS_INTERACTIVE_READ,
-    STATUS_IS_LOGIN,
-    STATUS_IS_NO_JOB_CTRL,
-    STATUS_LINE_NUMBER,
-    STATUS_LIST_FILES,
-    STATUS_SET_JOB_CONTROL,
-    STATUS_STACK_TRACE,
-    STATUS_TERMINAL,
-    STATUS_TERMINAL_OS,
-    STATUS_TEST_FEATURE,
-    STATUS_TEST_TERMINAL_FEATURE,
-}
-
 str_enum!(
     StatusCmd,
-    (STATUS_BASENAME, "basename"),
-    (STATUS_BASENAME, "current-basename"),
-    (STATUS_BUILD_INFO, "build-info"),
-    (STATUS_BUILD_INFO, "buildinfo"),
+    (STATUS_BASENAME, "basename", "current-basename"),
+    (STATUS_BUILD_INFO, "build-info", "buildinfo"),
     (STATUS_CURRENT_CMD, "current-command"),
     (STATUS_CURRENT_COMMANDLINE, "current-commandline"),
-    (STATUS_DIRNAME, "current-dirname"),
-    (STATUS_DIRNAME, "dirname"),
+    (STATUS_DIRNAME, "dirname", "current-dirname"),
     (STATUS_FEATURES, "features"),
-    (STATUS_FILENAME, "current-filename"),
-    (STATUS_FILENAME, "filename"),
+    (STATUS_FILENAME, "filename", "current-filename"),
     (STATUS_FISH_PATH, "fish-path"),
-    (STATUS_FUNCTION, "current-function"),
-    (STATUS_FUNCTION, "function"),
+    (STATUS_FUNCTION, "function", "current-function"),
     (STATUS_GET_FILE, "get-file"),
     (STATUS_IS_BLOCK, "is-block"),
     (STATUS_IS_BREAKPOINT, "is-breakpoint"),
@@ -95,12 +73,10 @@ enum StatusCmd {
     (STATUS_IS_INTERACTIVE_READ, "is-interactive-read"),
     (STATUS_IS_LOGIN, "is-login"),
     (STATUS_IS_NO_JOB_CTRL, "is-no-job-control"),
-    (STATUS_LINE_NUMBER, "current-line-number"),
-    (STATUS_LINE_NUMBER, "line-number"),
+    (STATUS_LINE_NUMBER, "line-number", "current-line-number"),
     (STATUS_LIST_FILES, "list-files"),
     (STATUS_SET_JOB_CONTROL, "job-control"),
-    (STATUS_STACK_TRACE, "print-stack-trace"),
-    (STATUS_STACK_TRACE, "stack-trace"),
+    (STATUS_STACK_TRACE, "stack-trace", "print-stack-trace"),
     (STATUS_TERMINAL, "terminal"),
     (STATUS_TERMINAL_OS, "terminal-os"),
     (STATUS_TEST_FEATURE, "test-feature"),
@@ -371,7 +347,7 @@ pub fn status(parser: &Parser, streams: &mut IoStreams, args: &mut [&wstr]) -> B
     // If a status command hasn't already been specified via a flag check the first word.
     // Note that this can be simplified after we eliminate allowing subcommands as flags.
     if optind < argc {
-        match StatusCmd::from_wstr(args[optind].to_string().as_str()) {
+        match StatusCmd::from_str(args[optind].to_string().as_str()) {
             Some(s) => {
                 if !opts.try_set_status_cmd(s, streams) {
                     return Err(STATUS_CMD_ERROR);