1 files changed, 30 insertions, 0 deletions
diff --git a/src/urubu/grammar/semantic_error.go b/src/urubu/grammar/semantic_error.go
new file mode 100644
index 0000000..88a6b17
--- /dev/null
+++ b/src/urubu/grammar/semantic_error.go
@@ -0,0 +1,30 @@
+package grammar
+
+import "errors"
+
+var (
+	semErrNoGrammarName         = errors.New("name is missing")
+	semErrSpellingInconsistency = errors.New("the identifiers are treated as the same. please use the same spelling")
+	semErrDuplicateAssoc        = errors.New("associativity and precedence cannot be specified multiple times for a symbol")
+	semErrUndefinedPrec         = errors.New("symbol must has precedence")
+	semErrUndefinedOrdSym       = errors.New("undefined ordered symbol")
+	semErrUnusedProduction      = errors.New("unused production")
+	semErrUnusedTerminal        = errors.New("unused terminal")
+	semErrTermCannotBeSkipped   = errors.New("a terminal used in productions cannot be skipped")
+	semErrNoProduction          = errors.New("a grammar needs at least one production")
+	semErrUndefinedSym          = errors.New("undefined symbol")
+	semErrDuplicateProduction   = errors.New("duplicate production")
+	semErrDuplicateTerminal     = errors.New("duplicate terminal")
+	semErrDuplicateFragment     = errors.New("duplicate fragment")
+	semErrDuplicateName         = errors.New("duplicate names are not allowed between terminals and non-terminals")
+	semErrErrSymIsReserved      = errors.New("symbol 'error' is reserved as a terminal symbol")
+	semErrDuplicateLabel        = errors.New("a label must be unique in an alternative")
+	semErrInvalidLabel          = errors.New("a label must differ from terminal symbols or non-terminal symbols")
+	semErrDirInvalidName        = errors.New("invalid directive name")
+	semErrDirInvalidParam       = errors.New("invalid parameter")
+	semErrDuplicateDir          = errors.New("a directive must not be duplicated")
+	semErrDuplicateElem         = errors.New("duplicate element")
+	semErrAmbiguousElem         = errors.New("ambiguous element")
+	semErrInvalidProdDir        = errors.New("invalid production directive")
+	semErrInvalidAltDir         = errors.New("invalid alternative directive")
+)