chore(idl): Check for case insensitive keywords

Most languages are not affected by this change. In PHP, some names such
as Bool cannot be used because it is a reserved keyword for to the bool
data type. The field `keywords_casing` in the configs enables checking
all characters in lowercase against every keyword. This should be safe
as flatbuffers does not allow non-ASCII characters in its grammar.

include/codegen/namer.h

@@ -91,6 +91,14 @@ class Namer {
     std::string keyword_prefix;
     // Suffix used to escape keywords. It is usually "_".
     std::string keyword_suffix;
+    // The casing used for keywords when escaping. For most languages, keywords
+    // are case sensitive. PHP is an instance where some keywords are case
+    // insensitive.
+    enum KeywordsCasing {
+      CASE_SENSITIVE,
+      CASE_INSENSITIVE,
+    };
+    KeywordsCasing keywords_casing;
 
     // Files.
 
@@ -205,7 +213,14 @@ class Namer {
   }
 
   virtual std::string EscapeKeyword(const std::string &name) const {
-    if (keywords_.find(name) == keywords_.end()) {
+    std::string cased_name(name);
+
+    if (config_.keywords_casing == Config::KeywordsCasing::CASE_INSENSITIVE) {
+      for (auto chr = cased_name.begin(); chr != cased_name.end(); chr++) {
+        *chr = CharToLower(*chr);
+      }
+    }
+    if (keywords_.find(cased_name) == keywords_.end()) {
       return name;
     } else {
       return config_.keyword_prefix + name + config_.keyword_suffix;

include/codegen/python.h

@@ -26,6 +26,7 @@ static const Namer::Config kConfig = {
     /*object_suffix=*/"T",
     /*keyword_prefix=*/"",
     /*keyword_suffix=*/"_",
+    /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
     /*filenames=*/Case::kKeep,
     /*directories=*/Case::kKeep,
     /*output_path=*/"",
@@ -49,6 +50,7 @@ static const Namer::Config kStubConfig = {
     /*object_suffix=*/"T",
     /*keyword_prefix=*/"",
     /*keyword_suffix=*/"_",
+    /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
     /*filenames=*/Case::kKeep,
     /*directories=*/Case::kKeep,
     /*output_path=*/"",

src/bfbs_gen_lua.cpp

@@ -61,6 +61,7 @@ Namer::Config LuaDefaultConfig() {
            /*object_suffix=*/"",
            /*keyword_prefix=*/"",
            /*keyword_suffix=*/"_",
+           /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
            /*filenames=*/Case::kKeep,
            /*directories=*/Case::kKeep,
            /*output_path=*/"",

src/bfbs_gen_nim.cpp

@@ -70,6 +70,7 @@ Namer::Config NimDefaultConfig() {
            /*object_suffix=*/"T",
            /*keyword_prefix=*/"",
            /*keyword_suffix=*/"_",
+           /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
            /*filenames=*/Case::kKeep,
            /*directories=*/Case::kKeep,
            /*output_path=*/"",

src/idl_gen_dart.cpp

@@ -48,6 +48,7 @@ static Namer::Config DartDefaultConfig() {
            /*object_suffix=*/"T",
            /*keyword_prefix=*/"$",
            /*keyword_suffix=*/"",
+           /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
            /*filenames=*/Case::kKeep,
            /*directories=*/Case::kKeep,
            /*output_path=*/"",

src/idl_gen_go.cpp

@@ -75,6 +75,7 @@ static Namer::Config GoDefaultConfig() {
            /*object_suffix=*/"T",
            /*keyword_prefix=*/"",
            /*keyword_suffix=*/"_",
+           /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
            /*filenames=*/Case::kKeep,
            /*directories=*/Case::kKeep,
            /*output_path=*/"",

src/idl_gen_java.cpp

@@ -46,6 +46,7 @@ static Namer::Config JavaDefaultConfig() {
     /*object_suffix=*/"T",
     /*keyword_prefix=*/"",
     /*keyword_suffix=*/"_",
+    /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
     /*filenames=*/Case::kKeep,
     /*directories=*/Case::kKeep,
     /*output_path=*/"",

src/idl_gen_kotlin.cpp

@@ -64,6 +64,7 @@ static Namer::Config KotlinDefaultConfig() {
            /*object_suffix=*/"T",
            /*keyword_prefix=*/"",
            /*keyword_suffix=*/"_",
+           /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
            /*filenames=*/Case::kKeep,
            /*directories=*/Case::kKeep,
            /*output_path=*/"",

src/idl_gen_kotlin_kmp.cpp

@@ -62,6 +62,7 @@ static Namer::Config KotlinDefaultConfig() {
            /*object_suffix=*/"T",
            /*keyword_prefix=*/"",
            /*keyword_suffix=*/"E",
+           /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
            /*filenames=*/Case::kUpperCamel,
            /*directories=*/Case::kLowerCamel,
            /*output_path=*/"",

src/idl_gen_rust.cpp

@@ -49,6 +49,7 @@ static Namer::Config RustDefaultConfig() {
            /*object_suffix=*/"T",
            /*keyword_prefix=*/"",
            /*keyword_suffix=*/"_",
+           /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
            /*filenames=*/Case::kSnake,
            /*directories=*/Case::kSnake,
            /*output_path=*/"",

src/idl_gen_swift.cpp

@@ -47,6 +47,7 @@ static Namer::Config SwiftDefaultConfig() {
            /*object_suffix=*/"T",
            /*keyword_prefix=*/"",
            /*keyword_suffix=*/"_",
+           /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
            /*filenames=*/Case::kKeep,
            /*directories=*/Case::kKeep,
            /*output_path=*/"",

src/idl_gen_ts.cpp

@@ -67,6 +67,7 @@ Namer::Config TypeScriptDefaultConfig() {
            /*object_suffix=*/"T",
            /*keyword_prefix=*/"",
            /*keyword_suffix=*/"_",
+           /*keywords_casing=*/Namer::Config::KeywordsCasing::CASE_SENSITIVE,
            /*filenames=*/Case::kDasher,
            /*directories=*/Case::kDasher,
            /*output_path=*/"",