From 2d3dbdc3f8221710f6ea9c9a68753148fca4ef86 Mon Sep 17 00:00:00 2001
From: Carl Masak <carl@masak.org>
Date: Sat, 17 Jul 2021 00:24:48 +0800
Subject: [PATCH 1/3] Factor passes into a class hierarchy

I have a limited belief in class hierarchies. But I'm largely fine
with using base classes as interfaces. That's what's happening
here, all the passes are an implementation (rather than a derived
class) of an abstract class (interface) `Pass`, of which we expect
certain things.
---
 lib/Language/Bel/Compiler.pm        | 29 +++++++++++++++--------------
 lib/Language/Bel/Compiler/Pass.pm   | 24 ++++++++++++++++++++++++
 lib/Language/Bel/Compiler/Pass01.pm | 15 ++++++++-------
 lib/Language/Bel/Compiler/Pass02.pm | 17 +++++++++--------
 lib/Language/Bel/Compiler/Pass03.pm | 15 ++++++++-------
 5 files changed, 64 insertions(+), 36 deletions(-)
 create mode 100644 lib/Language/Bel/Compiler/Pass.pm

diff --git a/lib/Language/Bel/Compiler.pm b/lib/Language/Bel/Compiler.pm
index 1eb19773..7e525fd5 100644
--- a/lib/Language/Bel/Compiler.pm
+++ b/lib/Language/Bel/Compiler.pm
@@ -4,30 +4,31 @@ use 5.006;
 use strict;
 use warnings;
 
-use Language::Bel::Compiler::Pass01 qw(
-    nanopass_01_alpha
-);
-use Language::Bel::Compiler::Pass02 qw(
-    nanopass_02_flatten
-);
-use Language::Bel::Compiler::Pass03 qw(
-    nanopass_03_allocate_registers
-);
+use Language::Bel::Compiler::Pass01;
+use Language::Bel::Compiler::Pass02;
+use Language::Bel::Compiler::Pass03;
 use Language::Bel::Compiler::Generator qw(
     generate_bytefunc
 );
 
 use Exporter 'import';
 
+my @PASSES = (
+    Language::Bel::Compiler::Pass01->new(),
+    Language::Bel::Compiler::Pass02->new(),
+    Language::Bel::Compiler::Pass03->new(),
+);
+
 sub compile {
     my ($source) = @_;
 
-    my $_00 = read_whole($source);
-    my $_01 = nanopass_01_alpha($_00);
-    my $_02 = nanopass_02_flatten($_01);
-    my $_03 = nanopass_03_allocate_registers($_02);
+    my $program = read_whole($source);
+
+    for my $nanopass (@PASSES) {
+        $program = $nanopass->translate($program);
+    }
 
-    return generate_bytefunc($_03);
+    return generate_bytefunc($program);
 }
 
 our @EXPORT_OK = qw(
diff --git a/lib/Language/Bel/Compiler/Pass.pm b/lib/Language/Bel/Compiler/Pass.pm
new file mode 100644
index 00000000..6653e089
--- /dev/null
+++ b/lib/Language/Bel/Compiler/Pass.pm
@@ -0,0 +1,24 @@
+package Language::Bel::Compiler::Pass;
+
+use 5.006;
+use strict;
+use warnings;
+
+sub new {
+    my ($class, $name) = @_;
+
+    return bless({
+        name => $name,
+    }, $class);
+}
+
+# abstract
+sub translate {
+    my ($self) = @_;
+
+    my $name = $self->{name};
+
+    die "The [$name] pass doesn't implement a 'translate' method";
+}
+
+1;
diff --git a/lib/Language/Bel/Compiler/Pass01.pm b/lib/Language/Bel/Compiler/Pass01.pm
index 0969e7b4..480f1a91 100644
--- a/lib/Language/Bel/Compiler/Pass01.pm
+++ b/lib/Language/Bel/Compiler/Pass01.pm
@@ -1,4 +1,5 @@
 package Language::Bel::Compiler::Pass01;
+use base qw(Language::Bel::Compiler::Pass);
 
 use 5.006;
 use strict;
@@ -24,7 +25,11 @@ use Language::Bel::Compiler::Gensym qw(
     gensym
 );
 
-use Exporter 'import';
+sub new {
+    my ($class) = @_;
+
+    return $class->SUPER::new("alpha");
+}
 
 sub replace_variables {
     my ($ast, $translation_ref) = @_;
@@ -43,8 +48,8 @@ sub replace_variables {
     }
 }
 
-sub nanopass_01_alpha {
-    my ($ast) = @_;
+sub translate {
+    my ($self, $ast) = @_;
 
     $ast = cdr($ast);
     my $fn_name = car($ast);
@@ -81,8 +86,4 @@ sub nanopass_01_alpha {
     );
 }
 
-our @EXPORT_OK = qw(
-    nanopass_01_alpha
-);
-
 1;
diff --git a/lib/Language/Bel/Compiler/Pass02.pm b/lib/Language/Bel/Compiler/Pass02.pm
index 976b6f42..d0bb4ad2 100644
--- a/lib/Language/Bel/Compiler/Pass02.pm
+++ b/lib/Language/Bel/Compiler/Pass02.pm
@@ -1,4 +1,5 @@
 package Language::Bel::Compiler::Pass02;
+use base qw(Language::Bel::Compiler::Pass);
 
 use 5.006;
 use strict;
@@ -28,13 +29,17 @@ use Language::Bel::Compiler::Primitives qw(
     cdr
 );
 
-use Exporter 'import';
-
 my %arg_count_of = (
     "id" => 2,
     "type" => 1,
 );
 
+sub new {
+    my ($class) = @_;
+
+    return $class->SUPER::new("flatten");
+}
+
 sub is_primitive {
     my ($op) = @_;
 
@@ -130,8 +135,8 @@ sub listify {
     return $list;
 }
 
-sub nanopass_02_flatten {
-    my ($ast) = @_;
+sub translate {
+    my ($self, $ast) = @_;
 
     $ast = cdr($ast);
     # skipping $fn_name
@@ -166,8 +171,4 @@ sub nanopass_02_flatten {
     );
 }
 
-our @EXPORT_OK = qw(
-    nanopass_02_flatten
-);
-
 1;
diff --git a/lib/Language/Bel/Compiler/Pass03.pm b/lib/Language/Bel/Compiler/Pass03.pm
index 11f85e35..01f710b5 100644
--- a/lib/Language/Bel/Compiler/Pass03.pm
+++ b/lib/Language/Bel/Compiler/Pass03.pm
@@ -1,4 +1,5 @@
 package Language::Bel::Compiler::Pass03;
+use base qw(Language::Bel::Compiler::Pass);
 
 use 5.006;
 use strict;
@@ -18,7 +19,11 @@ use Language::Bel::Compiler::Primitives qw(
     cdr
 );
 
-use Exporter 'import';
+sub new {
+    my ($class) = @_;
+
+    return $class->SUPER::new("allocate-registers");
+}
 
 sub substitute_registers {
     my ($expr) = @_;
@@ -37,8 +42,8 @@ sub substitute_registers {
     }
 }
 
-sub nanopass_03_allocate_registers {
-    my ($ast) = @_;
+sub translate {
+    my ($self, $ast) = @_;
 
     $ast = cdr($ast);
     my $args = substitute_registers(car($ast));
@@ -54,8 +59,4 @@ sub nanopass_03_allocate_registers {
     );
 }
 
-our @EXPORT_OK = qw(
-    nanopass_03_allocate_registers
-);
-
 1;

From d7a5c2acb45b3fde8e219b278264306d2a819770 Mon Sep 17 00:00:00 2001
From: Carl Masak <carl@masak.org>
Date: Sat, 17 Jul 2021 00:45:19 +0800
Subject: [PATCH 2/3] Rename modules

Names are better than numbers.
---
 lib/Language/Bel/Compiler.pm                         | 12 ++++++------
 .../{Pass03.pm => Pass/AllocateRegisters.pm}         |  2 +-
 .../Bel/Compiler/{Pass01.pm => Pass/Alpha.pm}        |  2 +-
 .../Bel/Compiler/{Pass02.pm => Pass/Flatten.pm}      |  2 +-
 4 files changed, 9 insertions(+), 9 deletions(-)
 rename lib/Language/Bel/Compiler/{Pass03.pm => Pass/AllocateRegisters.pm} (94%)
 rename lib/Language/Bel/Compiler/{Pass01.pm => Pass/Alpha.pm} (97%)
 rename lib/Language/Bel/Compiler/{Pass02.pm => Pass/Flatten.pm} (98%)

diff --git a/lib/Language/Bel/Compiler.pm b/lib/Language/Bel/Compiler.pm
index 7e525fd5..44d3f7c2 100644
--- a/lib/Language/Bel/Compiler.pm
+++ b/lib/Language/Bel/Compiler.pm
@@ -4,9 +4,9 @@ use 5.006;
 use strict;
 use warnings;
 
-use Language::Bel::Compiler::Pass01;
-use Language::Bel::Compiler::Pass02;
-use Language::Bel::Compiler::Pass03;
+use Language::Bel::Compiler::Pass::AllocateRegisters;
+use Language::Bel::Compiler::Pass::Alpha;
+use Language::Bel::Compiler::Pass::Flatten;
 use Language::Bel::Compiler::Generator qw(
     generate_bytefunc
 );
@@ -14,9 +14,9 @@ use Language::Bel::Compiler::Generator qw(
 use Exporter 'import';
 
 my @PASSES = (
-    Language::Bel::Compiler::Pass01->new(),
-    Language::Bel::Compiler::Pass02->new(),
-    Language::Bel::Compiler::Pass03->new(),
+    Language::Bel::Compiler::Pass::Alpha->new(),
+    Language::Bel::Compiler::Pass::Flatten->new(),
+    Language::Bel::Compiler::Pass::AllocateRegisters->new(),
 );
 
 sub compile {
diff --git a/lib/Language/Bel/Compiler/Pass03.pm b/lib/Language/Bel/Compiler/Pass/AllocateRegisters.pm
similarity index 94%
rename from lib/Language/Bel/Compiler/Pass03.pm
rename to lib/Language/Bel/Compiler/Pass/AllocateRegisters.pm
index 01f710b5..d2dbba94 100644
--- a/lib/Language/Bel/Compiler/Pass03.pm
+++ b/lib/Language/Bel/Compiler/Pass/AllocateRegisters.pm
@@ -1,4 +1,4 @@
-package Language::Bel::Compiler::Pass03;
+package Language::Bel::Compiler::Pass::AllocateRegisters;
 use base qw(Language::Bel::Compiler::Pass);
 
 use 5.006;
diff --git a/lib/Language/Bel/Compiler/Pass01.pm b/lib/Language/Bel/Compiler/Pass/Alpha.pm
similarity index 97%
rename from lib/Language/Bel/Compiler/Pass01.pm
rename to lib/Language/Bel/Compiler/Pass/Alpha.pm
index 480f1a91..2af70df9 100644
--- a/lib/Language/Bel/Compiler/Pass01.pm
+++ b/lib/Language/Bel/Compiler/Pass/Alpha.pm
@@ -1,4 +1,4 @@
-package Language::Bel::Compiler::Pass01;
+package Language::Bel::Compiler::Pass::Alpha;
 use base qw(Language::Bel::Compiler::Pass);
 
 use 5.006;
diff --git a/lib/Language/Bel/Compiler/Pass02.pm b/lib/Language/Bel/Compiler/Pass/Flatten.pm
similarity index 98%
rename from lib/Language/Bel/Compiler/Pass02.pm
rename to lib/Language/Bel/Compiler/Pass/Flatten.pm
index d0bb4ad2..97b700ce 100644
--- a/lib/Language/Bel/Compiler/Pass02.pm
+++ b/lib/Language/Bel/Compiler/Pass/Flatten.pm
@@ -1,4 +1,4 @@
-package Language::Bel::Compiler::Pass02;
+package Language::Bel::Compiler::Pass::Flatten;
 use base qw(Language::Bel::Compiler::Pass);
 
 use 5.006;

From b3d971c73bed986ff61a100a5e1720e97a3f48d1 Mon Sep 17 00:00:00 2001
From: Carl Masak <carl@masak.org>
Date: Sat, 17 Jul 2021 01:05:57 +0800
Subject: [PATCH 3/3] Simplify pass generation

---
 lib/Language/Bel/Compiler.pm | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/Language/Bel/Compiler.pm b/lib/Language/Bel/Compiler.pm
index 44d3f7c2..d613dc01 100644
--- a/lib/Language/Bel/Compiler.pm
+++ b/lib/Language/Bel/Compiler.pm
@@ -13,11 +13,17 @@ use Language::Bel::Compiler::Generator qw(
 
 use Exporter 'import';
 
-my @PASSES = (
-    Language::Bel::Compiler::Pass::Alpha->new(),
-    Language::Bel::Compiler::Pass::Flatten->new(),
-    Language::Bel::Compiler::Pass::AllocateRegisters->new(),
-);
+sub make_pass {
+    my ($name) = @_;
+
+    return "Language::Bel::Compiler::Pass::$name"->new();
+}
+
+my @PASSES = map { make_pass($_) } qw<
+    Alpha
+    Flatten
+    AllocateRegisters
+>;
 
 sub compile {
     my ($source) = @_;