1 files changed, 36 insertions, 0 deletions
diff --git a/grammar/lexical/parser/error.go b/grammar/lexical/parser/error.go
new file mode 100644
index 0000000..be81da4
--- /dev/null
+++ b/grammar/lexical/parser/error.go
@@ -0,0 +1,36 @@
+package parser
+
+import "fmt"
+
+var (
+	ParseErr = fmt.Errorf("parse error")
+
+	// lexical errors
+	synErrIncompletedEscSeq     = fmt.Errorf("incompleted escape sequence; unexpected EOF following \\")
+	synErrInvalidEscSeq         = fmt.Errorf("invalid escape sequence")
+	synErrInvalidCodePoint      = fmt.Errorf("code points must consist of just 4 or 6 hex digits")
+	synErrCharPropInvalidSymbol = fmt.Errorf("invalid character property symbol")
+	SynErrFragmentInvalidSymbol = fmt.Errorf("invalid fragment symbol")
+
+	// syntax errors
+	synErrUnexpectedToken        = fmt.Errorf("unexpected token")
+	synErrNullPattern            = fmt.Errorf("a pattern must be a non-empty byte sequence")
+	synErrUnmatchablePattern     = fmt.Errorf("a pattern cannot match any characters")
+	synErrAltLackOfOperand       = fmt.Errorf("an alternation expression must have operands")
+	synErrRepNoTarget            = fmt.Errorf("a repeat expression must have an operand")
+	synErrGroupNoElem            = fmt.Errorf("a grouping expression must include at least one character")
+	synErrGroupUnclosed          = fmt.Errorf("unclosed grouping expression")
+	synErrGroupNoInitiator       = fmt.Errorf(") needs preceding (")
+	synErrGroupInvalidForm       = fmt.Errorf("invalid grouping expression")
+	synErrBExpNoElem             = fmt.Errorf("a bracket expression must include at least one character")
+	synErrBExpUnclosed           = fmt.Errorf("unclosed bracket expression")
+	synErrBExpInvalidForm        = fmt.Errorf("invalid bracket expression")
+	synErrRangeInvalidOrder      = fmt.Errorf("a range expression with invalid order")
+	synErrRangePropIsUnavailable = fmt.Errorf("a property expression is unavailable in a range expression")
+	synErrRangeInvalidForm       = fmt.Errorf("invalid range expression")
+	synErrCPExpInvalidForm       = fmt.Errorf("invalid code point expression")
+	synErrCPExpOutOfRange        = fmt.Errorf("a code point must be between U+0000 to U+10FFFF")
+	synErrCharPropExpInvalidForm = fmt.Errorf("invalid character property expression")
+	synErrCharPropUnsupported    = fmt.Errorf("unsupported character property")
+	synErrFragmentExpInvalidForm = fmt.Errorf("invalid fragment expression")
+)