From 7020e1a5091402e2a63d237ef038745d30a1569b Mon Sep 17 00:00:00 2001
From: "R. Tyler Croy" <rtyler@brokenco.de>
Date: Sat, 23 Feb 2019 11:31:06 -0800
Subject: [PATCH] Add some tooling to bring in Antlr4 for eventually parsing
 .otto files

The thoughts are still swirling around in my head a bit, but given the current
targets that Antlr4 supports, I fear that .otto file parsing will need to be
handled in JavaScript or C++.
---
 Makefile           | 42 ++++++++++++++++++++++++++++++++++++++++++
 Otto.g4            |  4 ++++
 build/.gitignore   |  1 +
 contrib/.gitignore |  1 +
 scripts/prereqs.sh | 29 +++++++++++++++++++++++++++++
 5 files changed, 77 insertions(+)
 create mode 100644 Makefile
 create mode 100644 Otto.g4
 create mode 100644 build/.gitignore
 create mode 100644 contrib/.gitignore
 create mode 100644 scripts/prereqs.sh

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..c71bd94
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,42 @@
+
+
+ANTLR_BIN=antlr-4.7.2-complete.jar
+ANTLR=contrib/$(ANTLR_BIN)
+GRAMMAR=Otto.g4
+################################################################################
+## Phony targets
+all: help
+
+check: ## Run validation tests
+
+depends: prereqs $(ANTLR) ## Download all dependencies
+
+prereqs: scripts/prereqs.sh ## Check that this system has the necessary tools to build otto
+	@sh scripts/prereqs.sh
+
+clean: ## Clean all temporary/working files
+	rm -f $(ANTLR)
+
+
+parser: depends $(GRAMMAR) ## Generate the parser code
+	@for target in JavaScript Go Cpp; do \
+		java -cp $(ANTLR) org.antlr.v4.Tool \
+			-Dlanguage=$$target \
+			-o build/$$target \
+			$(GRAMMAR); \
+		echo "--> Generated $$target stubs"; \
+	done;
+
+################################################################################
+## Non-phony targets
+$(ANTLR): ## Download the latest ANTLR4 binary
+	(cd contrib && wget https://www.antlr.org/download/$(ANTLR_BIN))
+
+################################################################################
+
+# Cute hack thanks to:
+# https://marmelab.com/blog/2016/02/29/auto-documented-makefile.html
+help: ## Display this help text
+	@grep -E '^[a-zA-Z_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
+
+.PHONY: all check clean depends
diff --git a/Otto.g4 b/Otto.g4
new file mode 100644
index 0000000..5ddb133
--- /dev/null
+++ b/Otto.g4
@@ -0,0 +1,4 @@
+grammar Otto;
+r  : 'hello' ID ;         // match keyword hello followed by an identifier
+ID : [a-z]+ ;             // match lower-case identifiers
+WS : [ \t\r\n]+ -> skip ; // skip spaces, tabs, newlines
diff --git a/build/.gitignore b/build/.gitignore
new file mode 100644
index 0000000..72e8ffc
--- /dev/null
+++ b/build/.gitignore
@@ -0,0 +1 @@
+*
diff --git a/contrib/.gitignore b/contrib/.gitignore
new file mode 100644
index 0000000..d392f0e
--- /dev/null
+++ b/contrib/.gitignore
@@ -0,0 +1 @@
+*.jar
diff --git a/scripts/prereqs.sh b/scripts/prereqs.sh
new file mode 100644
index 0000000..6c4567f
--- /dev/null
+++ b/scripts/prereqs.sh
@@ -0,0 +1,29 @@
+#!/bin/sh
+
+err() {
+    printf '\e[48;5;%dm' 196
+    echo -n ">> ${1}"
+    printf '\e[0m \n'
+}
+ok() {
+    printf '\e[48;5;%dm' 034
+    echo -n ">> ${1}"
+    printf '\e[0m \n'
+}
+
+which wget &> /dev/null
+if [ $? -ne 0 ]; then
+    err "Please ensure that \`wget\` is in your PATH"
+    exit 1;
+else
+    ok "wget is present"
+fi;
+
+which java &> /dev/null
+if [ $? -ne 0 ]; then
+    err "Please ensure that \`java\` is in your PATH"
+    exit 1;
+else
+    ok "Java is present"
+fi;
+