From 90ce0a544d705ef902ba30b8f855aa215f33f5f9 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Wed, 26 May 2021 14:27:03 +0200
Subject: [PATCH] The Racket preserves package needs a local copy of schema.prs
 for the package-builder to work. Use a git hook to keep it in sync with the
 master copy

---
 Makefile                                      |  2 +
 git-hooks/pre-commit                          |  6 ++
 .../preserves/preserves-schema/metaschema.rkt |  2 +-
 .../preserves/preserves-schema/schema.prs     | 92 +++++++++++++++++++
 setup.sh                                      | 18 ++++
 5 files changed, 119 insertions(+), 1 deletion(-)
 create mode 100755 git-hooks/pre-commit
 create mode 100644 implementations/racket/preserves/preserves-schema/schema.prs
 create mode 100755 setup.sh

diff --git a/Makefile b/Makefile
index 03ef341..2d0bd74 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,5 @@
+__ignored__ := $(shell ./setup.sh)
+
 PDFS=preserves.pdf preserves-schema.pdf
 
 all: $(PDFS)
diff --git a/git-hooks/pre-commit b/git-hooks/pre-commit
new file mode 100755
index 0000000..804638a
--- /dev/null
+++ b/git-hooks/pre-commit
@@ -0,0 +1,6 @@
+#!/bin/sh
+
+exec 1>&2
+
+# Ensure that various copies of schema.prs are in fact identical.
+cmp schema/schema.prs implementations/racket/preserves/preserves-schema/schema.prs
diff --git a/implementations/racket/preserves/preserves-schema/metaschema.rkt b/implementations/racket/preserves/preserves-schema/metaschema.rkt
index e0eb750..570d767 100644
--- a/implementations/racket/preserves/preserves-schema/metaschema.rkt
+++ b/implementations/racket/preserves/preserves-schema/metaschema.rkt
@@ -1,4 +1,4 @@
 #lang preserves-schema
 
 version 1 .
-include "../../../../schema/schema.prs" .
+include "./schema.prs" .
diff --git a/implementations/racket/preserves/preserves-schema/schema.prs b/implementations/racket/preserves/preserves-schema/schema.prs
new file mode 100644
index 0000000..9fba3e2
--- /dev/null
+++ b/implementations/racket/preserves/preserves-schema/schema.prs
@@ -0,0 +1,92 @@
+@<EmacsMode "-*- preserves -*-">
+
+; TODO: some kind of constants
+; TODO: rename "version" to "schema-version" ?
+
+version 1 .
+
+Bundle = <bundle @modules Modules>.
+Modules = { ModulePath: Schema ...:... }.
+
+Schema = <schema {
+  version: Version
+  embeddedType: EmbeddedTypeName
+  definitions: Definitions
+}>.
+
+; version 1 .
+Version = 1 .
+
+EmbeddedTypeName = Ref / #f.
+
+Definitions = { symbol: Definition ...:... }.
+
+Definition =
+  ; Pattern / Pattern / ...
+  / <or [@pattern0 NamedAlternative @pattern1 NamedAlternative @patternN NamedAlternative ...]>
+
+  ; Pattern & Pattern & ...
+  / <and [@pattern0 NamedPattern @pattern1 NamedPattern @patternN NamedPattern ...]>
+
+  ; Pattern
+  / Pattern
+.
+
+Pattern = SimplePattern / CompoundPattern .
+
+SimplePattern =
+  ; any
+  / =any
+
+  ; special builtins: bool, float, double, int, string, bytes, symbol
+  / <atom @atomKind AtomKind>
+
+  ; matches an embedded value in the input: embedded
+  / <embedded>
+
+  ; =symbol, <<lit> any>, or plain non-symbol atom
+  / <lit @value any>
+
+  ; [p ...] ----> <seqof <ref p>>; see also tuple* below.
+  / <seqof @pattern SimplePattern>
+
+  ; #{p} ----> <setof <ref p>>
+  / <setof @pattern SimplePattern>
+
+  ; {k: v, ...:...} ----> <dictof <ref k> <ref v>>
+  / <dictof @key SimplePattern @value SimplePattern>
+
+  ; symbol, symbol.symbol, symbol.symbol.symbol, ...
+  / Ref
+.
+
+CompoundPattern =
+  ; <label a b c> ----> <rec <lit label> <tuple [<ref a> <ref b> <ref c>]>>
+  ; except for record labels
+  ; <<rec> x y> ---> <rec <ref x> <ref y>>
+  / <rec @label NamedPattern @fields NamedPattern>
+
+  ; [a b c] ----> <tuple [<ref a> <ref b> <ref c>]>
+  / <tuple @patterns [NamedPattern ...]>
+
+  ; [a b c ...] ----> <tuple* [<ref a> <ref b>] <seqof <ref c>>>
+  ; TODO: [@fixed0 NamedPattern @fixedN NamedPattern ...]
+  / <tuple* @fixed [NamedPattern ...] @variable NamedSimplePattern>
+
+  ; {a: b, c: d} ----> <dict {a: <ref b>, c: <ref d>}>
+  / <dict @entries DictionaryEntries>
+.
+
+DictionaryEntries = { any: NamedSimplePattern ...:... }.
+
+AtomKind = =Boolean / =Float / =Double / =SignedInteger / =String / =ByteString / =Symbol .
+
+NamedAlternative = [@variantLabel string @pattern Pattern].
+
+NamedSimplePattern = @named NamedSimplePattern_ / @anonymous SimplePattern .
+NamedPattern = @named NamedSimplePattern_ / @anonymous Pattern .
+
+NamedSimplePattern_ = <named @name symbol @pattern SimplePattern>.
+
+Ref = <ref @module ModulePath @name symbol>.
+ModulePath = [symbol ...].
diff --git a/setup.sh b/setup.sh
new file mode 100755
index 0000000..67c08b0
--- /dev/null
+++ b/setup.sh
@@ -0,0 +1,18 @@
+#!/bin/sh
+#
+# Set up a git checkout of this repository for local dev use.
+
+exec 2>/dev/tty 1>&2
+
+set -e
+
+[ -d .git ] || exit 0
+
+for fullhook in ./git-hooks/*
+do
+    hook=$(basename "$fullhook")
+    [ -L .git/hooks/$hook ] || (
+        echo "Installing $hook hook"
+        ln -s ../../git-hooks/$hook .git/hooks/$hook
+    )
+done