93 lines
1.8 KiB
Go
93 lines
1.8 KiB
Go
package vm
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"regexp"
|
|
|
|
"git.defalsify.org/festive/state"
|
|
)
|
|
|
|
var (
|
|
inputRegexStr = "^[a-zA-Z0-9].*$"
|
|
inputRegex = regexp.MustCompile(inputRegexStr)
|
|
ctrlRegexStr = "^[<>_]$"
|
|
ctrlRegex = regexp.MustCompile(inputRegexStr)
|
|
symRegexStr = "^[a-zA-Z0-9][a-zA-Z0-9_]+$"
|
|
symRegex = regexp.MustCompile(inputRegexStr)
|
|
|
|
)
|
|
|
|
// CheckInput validates the given byte string as client input.
|
|
func CheckInput(input []byte) error {
|
|
if !inputRegex.Match(input) {
|
|
return fmt.Errorf("Input '%s' does not match input format /%s/", input, inputRegexStr)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// control characters for relative navigation.
|
|
func checkControl(input []byte) error {
|
|
if !ctrlRegex.Match(input) {
|
|
return fmt.Errorf("Input '%s' does not match 'control' format /%s/", input, ctrlRegexStr)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// CheckSym validates the given byte string as a node symbol.
|
|
func CheckSym(input []byte) error {
|
|
if !symRegex.Match(input) {
|
|
return fmt.Errorf("Input '%s' does not match 'sym' format /%s/", input, symRegexStr)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// route parsed target symbol to navigation state change method,
|
|
func applyTarget(target []byte, st *state.State, ctx context.Context) (string, uint16, error) {
|
|
var err error
|
|
var valid bool
|
|
sym, idx := st.Where()
|
|
|
|
err = CheckInput(target)
|
|
if err == nil {
|
|
valid = true
|
|
}
|
|
|
|
if !valid {
|
|
err = CheckSym(target)
|
|
if err == nil {
|
|
valid = true
|
|
}
|
|
}
|
|
|
|
if !valid {
|
|
err = checkControl(target)
|
|
if err == nil {
|
|
valid = true
|
|
}
|
|
}
|
|
|
|
switch target[0] {
|
|
case '_':
|
|
sym, err = st.Up()
|
|
if err != nil {
|
|
return sym, idx, err
|
|
}
|
|
case '>':
|
|
idx, err = st.Next()
|
|
if err != nil {
|
|
return sym, idx, err
|
|
}
|
|
case '<':
|
|
idx, err = st.Previous()
|
|
if err != nil {
|
|
return sym, idx, err
|
|
}
|
|
default:
|
|
sym = string(target)
|
|
st.Down(sym)
|
|
idx = 0
|
|
}
|
|
return sym, idx, nil
|
|
}
|