From 24c8a46b870bbd7feb69a918e9a66a3011ef5c14 Mon Sep 17 00:00:00 2001
From: Paul Buetow <paul@buetow.org>
Date: Mon, 19 Feb 2024 18:32:34 +0200
Subject: initial play around with code generation from C to Go in Raku

---
 internal/generated/Makefile       | 10 +++++--
 internal/generated/generate.raku  | 57 +++++++++++++++++++++++++++++++++++++++
 internal/generated/types/types.go | 39 +++++++++++++++++++++++++++
 3 files changed, 104 insertions(+), 2 deletions(-)
 create mode 100644 internal/generated/generate.raku
 create mode 100644 internal/generated/types/types.go

diff --git a/internal/generated/Makefile b/internal/generated/Makefile
index dd3c780..701d4f8 100644
--- a/internal/generated/Makefile
+++ b/internal/generated/Makefile
@@ -1,7 +1,13 @@
 all: generate
 
-.PHONY: generate
-generate:
+generate: types tracepoint_list
+
+.PHONY: types
+types:
+	cat ../c/types.h | raku generate.raku nqctogo | tee types/types.go
+
+.PHONY: tracepoint_list
+tracepoint_list:
 	echo 'package generated' > tracepoint_list.go
 	echo '' >> tracepoint_list.go
 	echo 'var TracepointList = []string{' >> tracepoint_list.go
diff --git a/internal/generated/generate.raku b/internal/generated/generate.raku
new file mode 100644
index 0000000..babb655
--- /dev/null
+++ b/internal/generated/generate.raku
@@ -0,0 +1,57 @@
+#!/usr/bin/env raku
+#
+# This Raku program takes a list of C struct and constant definitions and converts
+# it to valid Go code.
+
+#use Grammar::Debugger;
+
+# Not quite C
+grammar NQC {
+    rule TOP { <construct>* }
+    rule construct { <constant> | <statement> || <comment> }
+    rule constant { '#define' <identifier> <number> }
+    rule statement { <struct> ';' }
+    rule struct { 'struct' <identifier> '{' <member>+ %% ';' '}' }
+    rule member { <type> <identifier> <arraysize>? }
+    rule comment { <single-line-comment> | <multi-line-comment> }
+    rule single-line-comment { '//' <-[\n]>+ }
+    rule multi-line-comment { '/*' .*? '*/' }
+    token arraysize { '[' <identifier> ']' }
+    token type { 'char' | '__s32' | '__u32' | '__u64' }
+    token identifier { <[a..z A..Z 0..9 _]>+ }
+    token number { \d+ }
+}
+ 
+class NQCToGoActions {
+    method TOP($/) { make "package types\n\n" ~ $<construct>.map(*.made).join('') }
+    method construct($/) { make $<constant>.made // $<statement>.made // '' }
+    method statement($/) { make "\n" ~ $<struct>.made ~ "\n"; }
+    method constant($/) { make 'const ' ~ $<identifier> ~ ' = ' ~ $<number> ~ "\n" }
+
+    method struct($/) {
+        make 'type ' ~ $<identifier>.made ~ " struct \{\n\t" ~
+                       $<member>.map(*.made).join("\n\t") ~ "\n\}"
+    }
+
+    method member($/) {
+        make $<identifier>.made ~ ' ' ~ ($<arraysize> ?? $<arraysize> !! '') ~ $<type>.made
+    }
+
+    method type($/) {
+        make do given ~$/ {
+            when 'char' { 'byte' }
+            when '__s32' { 'int32' }
+            when '__u32' { 'uint32' }
+            when '__u64' { 'uint64' }
+        };
+    }
+
+    method identifier($/) {
+        # Convert identifier from snake_case (C) to CamelCase (Go)
+        make $/.Str.split('_').map(*.tc).join('')
+    }
+}
+
+multi sub MAIN('nqctogo') {
+    NQC.parse($*IN.slurp, :actions(NQCToGoActions.new)).made.say;
+}
diff --git a/internal/generated/types/types.go b/internal/generated/types/types.go
new file mode 100644
index 0000000..ba384fe
--- /dev/null
+++ b/internal/generated/types/types.go
@@ -0,0 +1,39 @@
+package types
+
+const MAX_PROGNAME_LENGTH = 16
+const OPENAT_ENTER_OP_ID = 1
+const OPENAT_EXIT_OP_ID = 2
+const OPEN_ENTER_OP_ID = 3
+const OPEN_EXIT_OP_ID = 4
+const CLOSE_ENTER_OP_ID = 5
+const CLOSE_EXIT_OP_ID = 6
+const WRITE_ENTER_OP_ID = 7
+const WRITE_EXIT_OP_ID = 8
+const WRITEV_ENTER_OP_ID = 9
+const WRITEV_EXIT_OP_ID = 10
+
+type NullEvent struct {
+	OpId uint32
+	PidTgid uint32
+	Time uint64
+}
+
+type FdEvent struct {
+	OpId uint32
+	PidTgid uint32
+	Time uint64
+	Fd int32
+}
+
+type OpenatEnterEvent struct {
+	OpId uint32
+	PidTgid uint32
+	Time uint64
+	Filename [MAX_FILENAME_LENGTH]byte
+	Comm [MAX_PROGNAME_LENGTH]byte
+}
+
+type Flags struct {
+	UidFilter uint32
+}
+
-- 
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