surrealpatch/sql/data.go
2016-11-04 09:58:11 +00:00

169 lines
3.4 KiB
Go

// Copyright © 2016 Abcum Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package sql
func (p *parser) parseData() (exp []Expr, err error) {
if tok, _, exi := p.mightBe(SET, DIFF, MERGE, CONTENT); exi {
if p.is(tok, SET) {
if exp, err = p.parseSet(); err != nil {
return nil, err
}
}
if p.is(tok, DIFF) {
if exp, err = p.parseDiff(); err != nil {
return nil, err
}
}
if p.is(tok, MERGE) {
if exp, err = p.parseMerge(); err != nil {
return nil, err
}
}
if p.is(tok, CONTENT) {
if exp, err = p.parseContent(); err != nil {
return nil, err
}
}
}
return
}
func (p *parser) parseSet() (mul []Expr, err error) {
for {
var tok Token
var lit string
one := &DataExpression{}
// The first part of a SET expression must
// always be an identifier, specifying a
// record field to set.
tok, lit, err = p.shouldBe(IDENT)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"field name"}}
}
one.LHS, err = p.declare(tok, lit)
if err != nil {
return nil, err
}
// The next query part must be a =, +=, or
// -= operator, as this is a SET expression
// and not a binary expression.
one.Op, lit, err = p.shouldBe(EQ, INC, DEC)
if err != nil {
return nil, err
}
// The next query part can be any expression
// including a parenthesised expression or a
// binary expression so handle accordingly.
one.RHS, err = p.parseExpr()
if err != nil {
return nil, err
}
// Append the single SET data expression to
// the array of data expressions.
mul = append(mul, one)
// Check to see if the next token is a comma
// and if not, then break out of the loop,
// otherwise repeat until we find no comma.
if _, _, exi := p.mightBe(COMMA); !exi {
break
}
}
return
}
func (p *parser) parseDiff() (exp []Expr, err error) {
one := &DiffExpression{}
tok, lit, err := p.shouldBe(JSON, ARRAY, PARAM)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"json"}}
}
one.JSON, err = p.declare(tok, lit)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"json"}}
}
exp = append(exp, one)
return
}
func (p *parser) parseMerge() (exp []Expr, err error) {
one := &MergeExpression{}
tok, lit, err := p.shouldBe(JSON, PARAM)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"json"}}
}
one.JSON, err = p.declare(tok, lit)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"json"}}
}
exp = append(exp, one)
return
}
func (p *parser) parseContent() (exp []Expr, err error) {
one := &ContentExpression{}
tok, lit, err := p.shouldBe(JSON, PARAM)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"json"}}
}
one.JSON, err = p.declare(tok, lit)
if err != nil {
return nil, &ParseError{Found: lit, Expected: []string{"json"}}
}
exp = append(exp, one)
return
}