Split parse_statements from parse_sql

`Parser::parse_sql()` is intended to be only a helper, the user should
be able to use it or not, without having to re-implement parts of the
parsing logic.

Author: nickolay

src/parser.rs

@@ -86,22 +86,26 @@ impl Parser {
         let mut tokenizer = Tokenizer::new(dialect, &sql);
         let tokens = tokenizer.tokenize()?;
         let mut parser = Parser::new(tokens);
+        parser.parse_statements()
+    }
+
+    /// Parse zero or more SQL statements delimited with semicolon.
+    pub fn parse_statements(&mut self) -> Result<Vec<Statement>, ParserError> {
         let mut stmts = Vec::new();
         let mut expecting_statement_delimiter = false;
-        debug!("Parsing sql '{}'...", sql);
         loop {
             // ignore empty statements (between successive statement delimiters)
-            while parser.consume_token(&Token::SemiColon) {
+            while self.consume_token(&Token::SemiColon) {
                 expecting_statement_delimiter = false;
             }
 
-            if parser.peek_token().is_none() {
+            if self.peek_token().is_none() {
                 break;
             } else if expecting_statement_delimiter {
-                return parser.expected("end of statement", parser.peek_token());
+                return self.expected("end of statement", self.peek_token());
             }
 
-            let statement = parser.parse_statement()?;
+            let statement = self.parse_statement()?;
             stmts.push(statement);
             expecting_statement_delimiter = true;
         }