New Grammars Compiler (#3915)

* grammars: Update several grammars with compat issues

* [WIP] Add new grammar conversion tools

* Wrap in a Docker script

* Proper Dockerfile support

* Add Javadoc grammar

* Remove NPM package.json

* Remove superfluous test

This is now always checked by the grammars compiler

* Update JSyntax grammar to new submodule

* Approve Javadoc license

* grammars: Remove checked-in dependencies

* grammars: Add regex checks to the compiler

* grammars: Point Oz to its actual submodule

* grammars: Refactor compiler to group errors by repo

* grammars: Cleanups to error reporting

tools/grammars/pcre/pcre.go

@@ -0,0 +1,53 @@
+package pcre
+
+/*
+#cgo LDFLAGS: -lpcre
+#include <pcre.h>
+*/
+import "C"
+
+import (
+	"fmt"
+	"strings"
+	"unsafe"
+)
+
+func RegexPP(re string) string {
+	if len(re) > 32 {
+		re = fmt.Sprintf("\"`%s`...\"", re[:32])
+	} else {
+		re = fmt.Sprintf("\"`%s`\"", re)
+	}
+	return strings.Replace(re, "\n", "", -1)
+}
+
+type CompileError struct {
+	Pattern string
+	Message string
+	Offset  int
+}
+
+func (e *CompileError) Error() string {
+	return fmt.Sprintf("regex %s: %s (at offset %d)",
+		RegexPP(e.Pattern), e.Message, e.Offset)
+}
+
+const DefaultFlags = int(C.PCRE_DUPNAMES | C.PCRE_UTF8 | C.PCRE_NEWLINE_ANYCRLF)
+
+func CheckRegexp(pattern string, flags int) error {
+	pattern1 := C.CString(pattern)
+	defer C.free(unsafe.Pointer(pattern1))
+
+	var errptr *C.char
+	var erroffset C.int
+	ptr := C.pcre_compile(pattern1, C.int(flags), &errptr, &erroffset, nil)
+	if ptr == nil {
+		return &CompileError{
+			Pattern: pattern,
+			Message: C.GoString(errptr),
+			Offset:  int(erroffset),
+		}
+	}
+	C.free(unsafe.Pointer(ptr))
+	return nil
+}