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Simplify by using expect_keyword / expect_token (3/8)

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...instead of parse_keyword / consume_token - to reduce nesting of `if`s.

(Follow-up to PR #35)
This commit is contained in:
Nickolay Ponomarev 2019-01-14 00:42:07 +03:00
parent f87230553e
commit 8c3479969f
1 changed files with 49 additions and 64 deletions
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113
src/sqlparser.rs
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@ -589,19 +589,16 @@ impl Parser {
} else if is_unique_key {
Ok(TableKey::UniqueKey(key))
} else if is_foreign_key {
if self.parse_keyword("REFERENCES") {
let foreign_table = self.parse_tablename()?;
self.expect_token(&Token::LParen)?;
let referred_columns = self.parse_column_names()?;
self.expect_token(&Token::RParen)?;
Ok(TableKey::ForeignKey {
key,
foreign_table,
referred_columns,
})
} else {
parser_err!("Expecting references")
}
self.expect_keyword("REFERENCES")?;
let foreign_table = self.parse_tablename()?;
self.expect_token(&Token::LParen)?;
let referred_columns = self.parse_column_names()?;
self.expect_token(&Token::RParen)?;
Ok(TableKey::ForeignKey {
key,
foreign_table,
referred_columns,
})
} else {
parser_err!(format!(
"Expecting primary key, unique key, or foreign key, found: {:?}",
@ -611,39 +608,33 @@ impl Parser {
}
pub fn parse_alter(&mut self) -> Result<ASTNode, ParserError> {
if self.parse_keyword("TABLE") {
let _ = self.parse_keyword("ONLY");
let table_name = self.parse_tablename()?;
let operation: Result<AlterOperation, ParserError> =
if self.parse_keywords(vec!["ADD", "CONSTRAINT"]) {
match self.next_token() {
Some(Token::SQLWord(ref id)) => {
let table_key = self.parse_table_key(&id.value)?;
Ok(AlterOperation::AddConstraint(table_key))
}
_ => {
return parser_err!(format!(
"Expecting identifier, found : {:?}",
self.peek_token()
));
}
self.expect_keyword("TABLE")?;
let _ = self.parse_keyword("ONLY");
let table_name = self.parse_tablename()?;
let operation: Result<AlterOperation, ParserError> =
if self.parse_keywords(vec!["ADD", "CONSTRAINT"]) {
match self.next_token() {
Some(Token::SQLWord(ref id)) => {
let table_key = self.parse_table_key(&id.value)?;
Ok(AlterOperation::AddConstraint(table_key))
}
} else {
return parser_err!(format!(
"Expecting ADD CONSTRAINT, found :{:?}",
self.peek_token()
));
};
Ok(ASTNode::SQLAlterTable {
name: table_name,
operation: operation?,
})
} else {
parser_err!(format!(
"Expecting TABLE after ALTER, found {:?}",
self.peek_token()
))
}
_ => {
return parser_err!(format!(
"Expecting identifier, found : {:?}",
self.peek_token()
));
}
}
} else {
return parser_err!(format!(
"Expecting ADD CONSTRAINT, found :{:?}",
self.peek_token()
));
};
Ok(ASTNode::SQLAlterTable {
name: table_name,
operation: operation?,
})
}
/// Parse a copy statement
@ -1142,26 +1133,20 @@ impl Parser {
let constraint = self.parse_expr(0)?;
Ok(JoinConstraint::On(constraint))
} else if self.parse_keyword("USING") {
if self.consume_token(&Token::LParen) {
let attributes = self
.parse_expr_list()?
.into_iter()
.map(|ast_node| match ast_node {
ASTNode::SQLIdentifier(ident) => Ok(ident),
unexpected => {
parser_err!(format!("Expected identifier, found {:?}", unexpected))
}
})
.collect::<Result<Vec<String>, ParserError>>()?;
self.expect_token(&Token::LParen)?;
let attributes = self
.parse_expr_list()?
.into_iter()
.map(|ast_node| match ast_node {
ASTNode::SQLIdentifier(ident) => Ok(ident),
unexpected => {
parser_err!(format!("Expected identifier, found {:?}", unexpected))
}
})
.collect::<Result<Vec<String>, ParserError>>()?;
if self.consume_token(&Token::RParen) {
Ok(JoinConstraint::Using(attributes))
} else {
parser_err!(format!("Expected token ')', found {:?}", self.peek_token()))
}
} else {
parser_err!(format!("Expected token '(', found {:?}", self.peek_token()))
}
self.expect_token(&Token::RParen)?;
Ok(JoinConstraint::Using(attributes))
} else {
parser_err!(format!(
"Unexpected token after JOIN: {:?}",