Moving some documentation into the linter README.md.

Cleaned up the violation message (remove code duplication).

verilog/analysis/checkers/README.md

@@ -12,4 +12,4 @@ User documentation for the lint rules is generated dynamically, and can be found
 at https://chipsalliance.github.io/verible/verilog_lint.html, or by running
 `verible-verilog-lint --help_rules` for text or `--generate_markdown`.
 
-[Linter user documentation can be found here](../../tool/lint).
+[Linter user documentation can be found here](../../tools/lint).

verilog/analysis/checkers/enum_name_style_rule.cc

@@ -48,27 +48,19 @@ static constexpr absl::string_view style_default_regex = "[a-z_0-9]+(_t|_e)";
 
 EnumNameStyleRule::EnumNameStyleRule()
     : style_regex_(
-          std::make_unique<re2::RE2>(style_default_regex, re2::RE2::Quiet)),
-      violation_message_(absl::StrCat(
-          "Enum type name does not match the naming convention ",
-          "defined by regex pattern: ", style_regex_->pattern())) {}
+          std::make_unique<re2::RE2>(style_default_regex, re2::RE2::Quiet)) {}
 
 const LintRuleDescriptor &EnumNameStyleRule::GetDescriptor() {
   static const LintRuleDescriptor d{
       .name = "enum-name-style",
       .topic = "enumerations",
       .desc =
-          "Checks that enum type names follow a naming convention defined by "
-          "a RE2 regular expression.\n"
-          "Example common regex patterns:\n"
-          "  lower_snake_case: \"[a-z_0-9]+\"\n"
-          "  UPPER_SNAKE_CASE: \"[A-Z_0-9]+\"\n"
-          "  Title_Snake_Case: \"[A-Z]+[a-z0-9]*(_[A-Z0-9]+[a-z0-9]*)*\"\n"
-          "  Sentence_snake_case: \"([A-Z0-9]+[a-z0-9]*_?)([a-z0-9]*_*)*\"\n"
-          "  camelCase: \"([a-z0-9]+[A-Z0-9]*)+\"\n"
-          "  PascalCaseRegexPattern: \"([A-Z0-9]+[a-z0-9]*)+\"\n"
-          "RE2 regular expression syntax documentation can be found at "
-          "https://github.com/google/re2/wiki/syntax\n",
+          "Checks that enum type names follow a naming convention defined by a "
+          "RE2 regular expression. The default regex pattern expects "
+          "\"lower_snake_case\" with either a \"_t\" or \"_e\" suffix. Refer "
+          "to "
+          "https://github.com/chipsalliance/verible/tree/master/verilog/tools/"
+          "lint#readme for more detail on verible regex patterns.",
       .param = {{"style_regex", std::string(style_default_regex),
                  "A regex used to check enum type name style."}},
   };
@@ -80,6 +72,11 @@ static const Matcher &TypedefMatcher() {
   return matcher;
 }
 
+std::string EnumNameStyleRule::CreateViolationMessage() {
+  return absl::StrCat("Enum type name does not match the naming convention ",
+                      "defined by regex pattern: ", style_regex_->pattern());
+}
+
 void EnumNameStyleRule::HandleSymbol(const verible::Symbol &symbol,
                                      const SyntaxTreeContext &context) {
   verible::matcher::BoundSymbolManager manager;
@@ -90,8 +87,8 @@ void EnumNameStyleRule::HandleSymbol(const verible::Symbol &symbol,
       const auto *identifier_leaf = GetIdentifierFromTypeDeclaration(symbol);
       const auto name = ABSL_DIE_IF_NULL(identifier_leaf)->get().text();
       if (!RE2::FullMatch(name, *style_regex_)) {
-        violations_.insert(
-            LintViolation(identifier_leaf->get(), violation_message_, context));
+        violations_.insert(LintViolation(identifier_leaf->get(),
+                                         CreateViolationMessage(), context));
       }
     } else {
       // Not an enum definition
@@ -104,13 +101,7 @@ absl::Status EnumNameStyleRule::Configure(absl::string_view configuration) {
   using verible::config::SetRegex;
   absl::Status s = verible::ParseNameValues(
       configuration, {{"style_regex", SetRegex(&style_regex_)}});
-  if (!s.ok()) return s;
-
-  violation_message_ =
-      absl::StrCat("Enum type name does not match the naming convention ",
-                   "defined by regex pattern: ", style_regex_->pattern());
-
-  return absl::OkStatus();
+  return s;
 }
 
 LintRuleStatus EnumNameStyleRule::Report() const {

verilog/analysis/checkers/enum_name_style_rule.h

@@ -41,6 +41,8 @@ class EnumNameStyleRule : public verible::SyntaxTreeLintRule {
 
   static const LintRuleDescriptor &GetDescriptor();
 
+  std::string CreateViolationMessage();
+
   void HandleSymbol(const verible::Symbol &symbol,
                     const verible::SyntaxTreeContext &context) final;
 
@@ -53,8 +55,6 @@ class EnumNameStyleRule : public verible::SyntaxTreeLintRule {
 
   // A regex to check the style against
   std::unique_ptr<re2::RE2> style_regex_;
-
-  std::string violation_message_;
 };
 
 }  // namespace analysis

verilog/analysis/checkers/interface_name_style_rule.cc

@@ -45,7 +45,7 @@ static constexpr absl::string_view kMessage =
     "Interface names must use lower_snake_case naming convention "
     "and end with _if.";
 
-const LintRuleDescriptor& InterfaceNameStyleRule::GetDescriptor() {
+const LintRuleDescriptor &InterfaceNameStyleRule::GetDescriptor() {
   static const LintRuleDescriptor d{
       .name = "interface-name-style",
       .topic = "interface-conventions",
@@ -56,16 +56,16 @@ const LintRuleDescriptor& InterfaceNameStyleRule::GetDescriptor() {
   return d;
 }
 
-static const Matcher& InterfaceMatcher() {
+static const Matcher &InterfaceMatcher() {
   static const Matcher matcher(NodekInterfaceDeclaration());
   return matcher;
 }
 
-void InterfaceNameStyleRule::HandleSymbol(const verible::Symbol& symbol,
-                                          const SyntaxTreeContext& context) {
+void InterfaceNameStyleRule::HandleSymbol(const verible::Symbol &symbol,
+                                          const SyntaxTreeContext &context) {
   verible::matcher::BoundSymbolManager manager;
   absl::string_view name;
-  const verible::TokenInfo* identifier_token;
+  const verible::TokenInfo *identifier_token;
   if (InterfaceMatcher().Matches(symbol, &manager)) {
     identifier_token = GetInterfaceNameToken(symbol);
     name = identifier_token->text();

verilog/tools/lint/README.md

@@ -157,6 +157,26 @@ Additionally, the `--rules_config` flag can be used to read configuration stored
 in a file. The syntax is the same as above, except the rules can be also
 separated with the newline character.
 
+### Regular Expressions
+Some lint rules allow users to use a regular expression to configure the rule. Verible utilises the RE2 regular expression library and full syntax documentation can be found at https://github.com/google/re2/wiki/syntax.
+
+```bash
+verible-verilog-lint --rules="enum-name-style=style_regex:[a-z_0-9]+(_t|_e)" ...
+```
+
+For naming style rules, the regex can be kept simple and not have to worry about 
+the beginning starting with a digit as this is already taken care of by the 
+lexer/parser. Below are some common naming style regex patterns that can be used.
+
+| Naming Style           | Regex Expression                           |
+|------------------------|--------------------------------------------|
+| lower\_snake\_case     | [a-z\_0-9]+                                |
+| UPPER\_SNAKE\_CASE     | [A-Z\_0-9]+                                |
+| Title\_Snake\_Case     | [A-Z]+[a-z0-9]\*(\_[A-Z0-9]+[a-z0-9]\*)\*  |
+| Sentence\_snake\_case  | ([A-Z0-9]+[a-z0-9]\*\_?)([a-z0-9]\*\_\*)\* |
+| camelCase              | ([a-z0-9]+[A-Z0-9]\*)+                     |
+| PascalCase             | ([A-Z0-9]+[a-z0-9]\*)+                     |
+
 ## Waiving Lint Violations {#lint-waiver}
 
 ### In-file waiver comments