sq/libsq/ast/ast.go
Neil O'Toole 980e49358e tidy up
2016-10-16 22:14:01 -06:00

116 lines
1.9 KiB
Go

package ast
import (
"fmt"
"github.com/neilotoole/go-lg/lg"
"github.com/neilotoole/sq/libsq/slq"
"github.com/pboyer/antlr4/runtime/Go/antlr"
)
// AST is sq's Abstract Syntax Tree.
type AST struct {
ctx *slq.QueryContext
Datasource string
segs []*Segment
}
func (a *AST) Parent() Node {
return nil
}
func (a *AST) SetParent(parent Node) error {
return errorf("root node (%T) cannot have parent: tried to add parent %T", a, parent)
}
func (a *AST) Children() []Node {
nodes := make([]Node, len(a.segs))
for i, seg := range a.segs {
nodes[i] = seg
}
return nodes
}
func (a *AST) Segments() []*Segment {
return a.segs
}
func (a *AST) AddChild(node Node) error {
seg, ok := node.(*Segment)
if !ok {
return errorf("expected *Segment but got: %T", node)
}
a.AddSegment(seg)
return nil
}
func (a *AST) SetChildren(children []Node) error {
segs := make([]*Segment, len(children))
for i, child := range children {
seg, ok := child.(*Segment)
if !ok {
return errorf("expected child of type %s, but got: %T", TypeSegment, child)
}
segs[i] = seg
}
a.segs = segs
return nil
}
func (a *AST) Context() antlr.ParseTree {
return a.ctx
}
func (a *AST) SetContext(ctx antlr.ParseTree) error {
qCtx, ok := ctx.(*slq.QueryContext)
if !ok {
return errorf("expected *parser.QueryContext, but got %T", ctx)
}
a.ctx = qCtx
return nil
}
func (a *AST) String() string {
return nodeString(a)
}
func (a *AST) Text() string {
return a.ctx.GetText()
}
// AddSegment appends seg to the IR.
func (a *AST) AddSegment(seg *Segment) {
seg.SetParent(a)
//a.bn.AddChild(seg)
a.segs = append(a.segs, seg)
}
// Error is an error generated within the ast package.
type Error struct {
msg string
}
func (e *Error) Error() string {
return e.msg
}
func errorf(format string, v ...interface{}) *Error {
err := &Error{msg: fmt.Sprintf(format, v...)}
lg.Depth(1).Warnf("error created: %s", err.msg)
return err
}