Merge pull request #4623 from japhb/support-terminal-lineeditor

Support Terminal::LineEditor in the Raku REPL

docs/line-editor.pod

@@ -9,9 +9,11 @@ provide much of the same functionality.
 
 =head2 AVAILABLE EDITORS
 
-Right now, there are new line editor modules available: C<Readline> and C<Linenoise>.
-They have roughly the same functionality, but C<Linenoise> provides tab completion,
-and C<Readline> has an easier time with multibyte input.
+Right now, there are three line editor modules available: C<Readline>,
+C<Linenoise>, and C<LineEditor> (installed via C<Terminal::LineEditor>).  They
+have roughly the same functionality, but C<Linenoise> provides tab completion,
+while C<Readline> and C<LineEditor> both have an easier time with multibyte
+input.
 
 =head2 ENVIRONMENT VARIABLES
 
@@ -27,13 +29,16 @@ This disables multi-line input for the REPL if truthy.
 =item RAKUDO_HIST
 
 This specifies the location of the history file used by the line editor; the
-default is C<~/.perl6/rakudo-history>.
+default is C<~/.raku/rakudo-history>.  Before Rakudo version 2020.02 the
+default was C<~/.perl6/rakudo-history>.  If the older default file exists and
+the newer one does not, it will be automatically migrated.
+
 
 =item RAKUDO_LINE_EDITOR
 
 This specifies the preferred line editor to use; valid values are C<Readline>,
-C<Linenoise>, and C<none>.  A value of C<none> is useful if you want to avoid
-the recommendation message upon REPL startup.
+C<Linenoise>, C<LineEditor>, and C<none>.  A value of C<none> is useful if you
+want to avoid the recommendation message upon REPL startup.
 
 =back
 

docs/running.pod

@@ -157,19 +157,19 @@ emitted.
 =item C<RAKUDO_LINE_EDITOR>
 
 This specifies the preferred line editor to use; valid values are C<Readline>,
-C<Linenoise>, and none. A value of none is useful if you want to avoid the
-recommendation message upon REPL startup.
+C<Linenoise>, C<LineEditor>, and C<none>. A value of C<none> is useful if you
+want to avoid the recommendation message upon REPL startup.
 
 =item C<RAKUDO_DISABLE_MULTILINE>
 
 If set to 1, will disable multiline input for the REPL.
 
 =item C<RAKUDO_HIST>
 
-This specifies the location of the history file used by the
-line editor; the default is C<~/.raku/rakudo-history>.
-Before Rakudo version 2020.02 the default was
-C<~/.perl6/rakudo-history>.
+This specifies the location of the history file used by the line editor; the
+default is C<~/.raku/rakudo-history>.  Before Rakudo version 2020.02 the
+default was C<~/.perl6/rakudo-history>.  If the older default file exists and
+the newer one does not, it will be automatically migrated.
 
 =back
 

src/core.c/REPL.pm6

@@ -100,6 +100,38 @@ do {
         }
     }
 
+    my role TerminalLineEditorBehavior[$WHO] {
+        my $cli-input = $WHO<CLIInput>;
+        my $cli;
+
+        method completions-for-line(Str $line, int $cursor-index) { ... }
+
+        method history-file(--> Str:D) { ... }
+
+        method init-line-editor {
+            my sub get-completions($contents, $pos) {
+                eager self.completions-for-line($contents, $pos)
+            }
+            $cli = $cli-input.new(:&get-completions);
+            $cli.load-history($.history-file);
+        }
+
+        method teardown-line-editor {
+            $cli.save-history($.history-file);
+        }
+
+        method repl-read(Mu \prompt) {
+            self.update-completions;
+            my $line = $cli.prompt(prompt);
+
+            if $line.defined && $line.match(/\S/) {
+                $cli.add-history($line);
+            }
+
+            $line
+        }
+    }
+
     my role FallbackBehavior {
         method repl-read(Mu \prompt) {
             print prompt;
@@ -171,7 +203,8 @@ do {
         has $!need-more-input = {};
         has $!control-not-allowed = {};
 
-        sub do-mixin($self, Str $module-name, $behavior, Str :$fallback) {
+        sub do-mixin($self, Str $module-name, $behavior, :@extra-modules,
+                     Str :$fallback, Bool :$classlike) {
             my Bool $problem = False;
             try {
                 CATCH {
@@ -190,8 +223,10 @@ do {
                     }
                 }
 
+                (require ::($_)) for @extra-modules;
                 my $module = do require ::($module-name);
-                my $new-self = $self but $behavior.^parameterize($module.WHO<EXPORT>.WHO<ALL>.WHO);
+                my $who = $classlike ?? $module.WHO !! $module.WHO<EXPORT>.WHO<ALL>.WHO;
+                my $new-self = $self but $behavior.^parameterize($who);
                 $new-self.?init-line-editor();
                 return ( $new-self, False );
             }
@@ -207,10 +242,17 @@ do {
             do-mixin($self, 'Linenoise', LinenoiseBehavior, |c)
         }
 
+        sub mixin-terminal-lineeditor($self, |c) {
+            do-mixin($self, 'Terminal::LineEditor', TerminalLineEditorBehavior,
+                     :extra-modules('Terminal::LineEditor::RawTerminalInput',),
+                     :classlike, |c)
+        }
+
         sub mixin-line-editor($self) {
             my %editor-to-mixin = (
                 :Linenoise(&mixin-linenoise),
                 :Readline(&mixin-readline),
+                :LineEditor(&mixin-terminal-lineeditor),
                 :none(-> $self { ( $self but FallbackBehavior, False ) }),
             );
 
@@ -231,15 +273,18 @@ do {
             my ( $new-self, $problem ) = mixin-readline($self, :fallback<Linenoise>);
             return $new-self if $new-self;
 
-            ( $new-self, $problem ) = mixin-linenoise($self);
+            ( $new-self, $problem ) = mixin-linenoise($self, :fallback<LineEditor>);
+            return $new-self if $new-self;
+
+            ( $new-self, $problem ) = mixin-terminal-lineeditor($self);
             return $new-self if $new-self;
 
             if $problem {
                 say 'Continuing without tab completions or line editor';
                 say 'You may want to consider using rlwrap for simple line editor functionality';
             }
             elsif !Rakudo::Internals.IS-WIN and !( %*ENV<_>:exists and %*ENV<_>.ends-with: 'rlwrap' ) {
-                say 'You may want to `zef install Readline` or `zef install Linenoise` or use rlwrap for a line editor';
+                say 'You may want to `zef install Readline`, `zef install Linenoise`, or `zef install Terminal::LineEditor` or use rlwrap for a line editor';
             }
             say '';
 

t/02-rakudo/repl.t

@@ -8,7 +8,8 @@ plan 47;
 my $eof = $*DISTRO.is-win ?? "'^Z'" !! "'^D'";
 my $*REPL-SCRUBBER = -> $_ is copy {
     $_ = .lines.skip(4).join("\n");
-    s/^^ "You may want to `zef install Readline` or `zef install Linenoise`"
+    s/^^ "You may want to `zef install Readline`, `zef install Linenoise`,"
+        " or `zef install Terminal::LineEditor`"
         " or use rlwrap for a line editor\n\n"//;
     s/^^ "To exit type 'exit' or $eof\n"//;
     s:g/ ^^ "> "  //; # Strip out the prompts
@@ -164,12 +165,13 @@ is-run-repl ['Nil'], /Nil/, 'REPL outputs Nil as a Nil';
     skip 'Result differs on OSX';
     # is-run-repl ['say "hi"'], {
     #     .subst(:g, /\W+/, '') eq
-    #     'YoumaywanttozefinstallReadlineorzefinstallLinenoise'
+    #     'YoumaywanttozefinstallReadlinezefinstallLinenoise'
+    #     ~ 'orzefinstallTerminalLineEditor'
     #     ~ 'oruserlwrapforalineeditor' ~ 'ToexittypeexitorD' ~ 'hi'
     # }, 'REPL session does not have unexpected stuff';
 
-    ## XXX TODO: need to write tests that exercise the REPL with Linenoise
-    # and Readline installed. Particular things to check:
+    ## XXX TODO: need to write tests that exercise the REPL with Linenoise,
+    # Readline, and Terminal::LineEditor installed. Particular things to check:
     # 1. History file can be made on all OSes:
     #    https://github.com/rakudo/rakudo/commit/b4fa6d6792dd02424d2182b73c31a071cddc0b8e
     # 2. Test REPL does not show errors when $*HOME is not set: