From e4bef0c4b71f42fe7c115ffc3ee1d7075910a7b1 Mon Sep 17 00:00:00 2001
From: Tobie Morgan Hitchcock <tobie@abcum.com>
Date: Fri, 24 Feb 2017 13:05:07 +0000
Subject: [PATCH] Differentiate between IDENT and EXPR in SQL
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Previously it was possible to CREATE/UPDATE/DELETE path expressions as this would satisfy an IDENT in the SQL parser.

Now however, there is a difference between an IDENT and an EXPR…

IDENT: person | person_main | person123
EXPR: person | person.path | person[0].path

As a result, path expressions are only possible when setting data or setting conditional conditions.
---
 sql/exprs.go   |  2 +-
 sql/scanner.go | 16 ++++++++++++----
 sql/tokens.go  |  1 +
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/sql/exprs.go b/sql/exprs.go
index a2f19ac6..699ef6a5 100644
--- a/sql/exprs.go
+++ b/sql/exprs.go
@@ -519,7 +519,7 @@ func (p *parser) parseExpr() (exp Expr, err error) {
 func (p *parser) parsePart() (exp Expr, err error) {
 
 	toks := []Token{
-		MUL, ID, IDENT, THING,
+		MUL, ID, EXPR, IDENT, THING,
 		NULL, VOID, EMPTY, MISSING,
 		TRUE, FALSE, STRING, REGION, NUMBER, DOUBLE,
 		NOW, DATE, TIME, DURATION, JSON, ARRAY, PARAM, LPAREN,
diff --git a/sql/scanner.go b/sql/scanner.go
index 2504f79d..62731128 100644
--- a/sql/scanner.go
+++ b/sql/scanner.go
@@ -395,11 +395,14 @@ func (s *scanner) scanIdent(chp ...rune) (tok Token, lit string, val interface{}
 	for {
 		if ch := s.next(); ch == eof {
 			break
-		} else if !isIdentChar(ch) {
+		} else if isIdentChar(ch) {
+			buf.WriteRune(ch)
+		} else if isExprsChar(ch) {
+			tok = EXPR
+			buf.WriteRune(ch)
+		} else {
 			s.undo()
 			break
-		} else {
-			buf.WriteRune(ch)
 		}
 	}
 
@@ -839,7 +842,7 @@ func isLetter(ch rune) bool {
 
 // isIdentChar returns true if the rune is allowed in a IDENT.
 func isIdentChar(ch rune) bool {
-	return isLetter(ch) || isNumber(ch) || ch == '.' || ch == '_' || ch == '*' || ch == '[' || ch == ']'
+	return isLetter(ch) || isNumber(ch) || ch == '_'
 }
 
 // isThingChar returns true if the rune is allowed in a THING.
@@ -847,5 +850,10 @@ func isThingChar(ch rune) bool {
 	return isLetter(ch) || isNumber(ch) || ch == '_'
 }
 
+// isExprsChar returns true if the rune is allowed in a IDENT.
+func isExprsChar(ch rune) bool {
+	return isLetter(ch) || isNumber(ch) || ch == '.' || ch == '_' || ch == '*' || ch == '[' || ch == ']'
+}
+
 // eof represents a marker rune for the end of the reader.
 var eof = rune(0)
diff --git a/sql/tokens.go b/sql/tokens.go
index 45e36cc9..a9dc940a 100644
--- a/sql/tokens.go
+++ b/sql/tokens.go
@@ -32,6 +32,7 @@ const (
 	DATE     // 1970-01-01
 	TIME     // 1970-01-01T00:00:00+00:00
 	JSON     // {"test":true}
+	EXPR     // something[0].value
 	IDENT    // something
 	THING    // @class:id
 	STRING   // "something"