forked from karlseguin/gerb
/
for.go
199 lines (171 loc) · 4.35 KB
/
for.go
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package gerb
import (
"errors"
"fmt"
"github.com/karlseguin/gerb/core"
"reflect"
)
func ForFactory(p *core.Parser) (core.Code, error) {
if p.TagContains(';') {
return ExplicitForFactory(p)
}
if p.SkipSpaces() == '{' {
p.Next()
return &ForCode{NormalContainer: new(core.NormalContainer)}, nil
}
return RangedForFactory(p)
}
func ExplicitForFactory(p *core.Parser) (core.Code, error) {
code := &ForCode{NormalContainer: new(core.NormalContainer)}
if p.SkipSpaces() != ';' {
assignment, err := p.ReadAssignment()
if err != nil {
return nil, err
}
code.init = assignment
}
if p.SkipSpaces() != ';' {
return nil, p.Error("Invalid for loop, expecting INIT; CONDITION; STEP (1)")
}
p.Next()
verifiable, err := p.ReadConditionGroup(false)
if err != nil {
return nil, err
}
code.verifiable = verifiable
if p.SkipSpaces() != ';' {
return nil, p.Error("Invalid for loop, expecting INIT; CONDITION; STEP (1)")
}
p.Next()
if p.SkipSpaces() != '{' {
value, err := p.ReadAssignment()
if err != nil {
return nil, err
}
code.step = value
}
if p.SkipSpaces() != '{' {
return nil, p.Error("Missing openening brace for for statement")
}
p.Next()
return code, nil
}
func RangedForFactory(p *core.Parser) (core.Code, error) {
code := &RangedForCode{NormalContainer: new(core.NormalContainer)}
tokens, err := p.ReadTokenList()
if err != nil {
return nil, err
}
if len(tokens) != 2 {
return nil, p.Error("Invalid for loop, ranged loop should have two variables")
}
code.tokens = tokens
c := p.SkipSpaces()
if c == ':' {
c = p.Next()
}
if c != '=' {
return nil, p.Error("Invalid for loop, ranged loop expecting assignment operator")
}
p.Next()
if p.SkipSpaces() != 'r' || p.ConsumeIf([]byte("range")) == false {
return nil, p.Error("invalid for loop, expected 'range' keyword")
}
value, err := p.ReadValue()
if err != nil {
return nil, err
}
code.value = value
if p.SkipSpaces() != '{' {
return nil, p.Error("Missing openening brace for if statement")
}
p.Next()
return code, nil
}
type ForCode struct {
*core.NormalContainer
init *core.Assignment
verifiable core.Verifiable
step *core.Assignment
}
func (c *ForCode) Execute(context *core.Context) core.ExecutionState {
if c.init != nil {
c.init.Execute(context)
}
for {
if c.verifiable != nil && c.verifiable.IsTrue(context) == false {
break
}
state := c.NormalContainer.Execute(context)
if state == core.BreakState {
break
}
if c.step != nil {
c.step.Execute(context)
}
}
return core.NormalState
}
func (c *ForCode) IsCodeContainer() bool {
return true
}
func (c *ForCode) IsContentContainer() bool {
return true
}
func (c *ForCode) IsSibling() bool {
return false
}
func (c *ForCode) AddCode(code core.Code) error {
return errors.New(fmt.Sprintf("%v is not a valid tag as a descendant of a for loop", code))
}
type RangedForCode struct {
*core.NormalContainer
tokens []string
value core.Value
}
func (c *RangedForCode) Execute(context *core.Context) core.ExecutionState {
value := reflect.ValueOf(c.value.Resolve(context))
kind := value.Kind()
if kind == reflect.Array || kind == reflect.Slice || kind == reflect.String || kind == reflect.Map {
length := value.Len()
if length == 0 {
return core.NormalState
}
if kind == reflect.Map {
c.executeMap(context, value, length)
} else {
c.executeArray(context, value, length)
}
}
delete(context.Data, c.tokens[0])
delete(context.Data, c.tokens[1])
return core.NormalState
}
func (c *RangedForCode) IsCodeContainer() bool {
return true
}
func (c *RangedForCode) IsContentContainer() bool {
return true
}
func (c *RangedForCode) IsSibling() bool {
return false
}
func (c *RangedForCode) AddCode(code core.Code) error {
return errors.New(fmt.Sprintf("%v is not a valid tag as a descendant of a for loop", code))
}
func (c *RangedForCode) executeArray(context *core.Context, value reflect.Value, length int) {
for i := 0; i < length; i++ {
context.Data[c.tokens[0]] = i
context.Data[c.tokens[1]] = value.Index(i).Interface()
c.NormalContainer.Execute(context)
}
}
func (c *RangedForCode) executeMap(context *core.Context, value reflect.Value, length int) {
keys := value.MapKeys()
for i := 0; i < length; i++ {
key := keys[i]
context.Data[c.tokens[0]] = key
context.Data[c.tokens[1]] = value.MapIndex(key).Interface()
c.NormalContainer.Execute(context)
}
}