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package main
import (
"bufio"
"io"
"main/json"
"main/walk"
"os"
)
type ProgramState struct {
value, xreg, yreg, zreg []walk.Value
start, prevStart, end, nextEnd bool
// TODO: This will only ever have 0 or 1 values, it is a slice out of laziness
peekStack []walk.WalkItem
in walk.StredReader
out walk.StredWriter
program []Command
pc int
}
func (state *ProgramState) Read() (walk.WalkItem, error) {
if len(state.peekStack) > 0 {
item := state.peekStack[len(state.peekStack) - 1]
state.peekStack = state.peekStack[:len(state.peekStack) - 1]
return item, nil
}
return state.in.Read()
}
func (state *ProgramState) Peek() (walk.WalkItem, error) {
item, err := state.Read()
if err != nil {
return walk.WalkItem{}, err
}
state.peekStack = append(state.peekStack, item)
return item, nil
}
type config struct {
quiet bool
program string
in io.Reader
out io.Writer
}
func run(config config) {
tokens := Lex(config.program)
program := Parse(tokens)
stdin := bufio.NewReader(config.in)
stdout := bufio.NewWriter(config.out)
state := ProgramState {
in: json.NewJSONReader(stdin),
out: json.NewJSONWriter(stdout),
program: program,
}
for {
walkItem, err := state.Read()
if err != nil {
break
}
state.value = []walk.Value{walkItem.Value}
state.start = walkItem.Start
state.prevStart = walkItem.PrevStart
state.end = walkItem.End
state.nextEnd = walkItem.NextEnd
state.pc = 0
for state.pc < len(state.program) {
state.program[state.pc].exec(&state)
}
if !config.quiet {
for _, value := range state.value {
err := state.out.Write(value)
if err != nil {
panic("Error while outputting")
}
}
}
}
state.in.AssertDone()
state.out.AssertDone()
}
func main() {
config := config {
quiet: false,
in: os.Stdin,
out: os.Stdout,
}
hasInput := false
for i := 1; i < len(os.Args); i += 1 {
switch os.Args[i] {
case "-n":
config.quiet = true
continue
}
if i < len(os.Args) - 1 {
panic("Unexpected arguments after program")
}
config.program = os.Args[i]
hasInput = true
}
if !hasInput {
panic("Missing program")
}
run(config)
}
|
