/
cc4584.go
468 lines (395 loc) · 9.28 KB
/
cc4584.go
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package main
import (
"bufio"
"os"
"fmt"
"strings"
)
var (
inputReader *bufio.Reader
input string
err error
strList []string
left []string
right []string
LHS string
RHS string
m map[string]string = make(map[string]string)
)
func main(){
inputReader = bufio.NewReader(os.Stdin)
for {
/* Get input from Screen */
input, err = inputReader.ReadString('\n')
/* Strip last "\n" */
input = strings.TrimSpace(input)
/* Split at "&" */
strList = strings.Split(input, "&")
/* Deal with "QUIT" */
if len(strList) == 1 {
if strings.TrimSpace(strList[0]) == "QUIT" {
os.Exit(1)
} else {
fmt.Printf("%s\n", "ERR")
os.Exit(1)
}
} else if len(strList) != 2 {
fmt.Printf("%s\n", "ERR")
os.Exit(1)
}
LHS = strings.TrimSpace(strList[0])
RHS = strings.TrimSpace(strList[1])
if isValidType(LHS) != true || isValidType(RHS) != true{
fmt.Printf("%s\n", "ERR")
os.Exit(1)
}
typeTokenizer(LHS, RHS)
typeUnify()
ret := outputFormating(LHS)
for k := 0; k < len(ret);k++ {
fmt.Printf("%s", ret[k])
}
fmt.Printf("\n")
}
}
func lengthOfTypeVar(s string) int {
var j int = 1
for ;j < len(s) ; j++ {
if !isLetter(s[j]) && !isDigit(s[j]) {
break
}
}
return j
}
func outputFormating(LHS string) []string{
var elem string
var ok bool
var ret []string
var start int = 0
for i := 0; i < len(LHS); i++ {
if LHS[i] == '`' {
ret = append(ret, LHS[start:i])
j := i + lengthOfTypeVar(LHS[i:len(LHS)])
elem, ok = m[LHS[i:j]]
/* No constrain about this variable type */
if !ok {
ret = append(ret, LHS[i:j])
} else {
/* This type unify with a Primitive Type */
if isValidPrimitive(elem){
ret = append(ret, elem)
} else {
/* Chainning Replace */
var seen map[string]string = make(map[string]string)
rep := typeRelacing(seen, LHS[i:j])
for k := 0; k < len(rep); k++ {
ret = append(ret, rep[k])
}
}
}
start = j
i = j
}
}
ret = append(ret, LHS[start:len(LHS)])
return ret
}
func typeRelacing(seen map[string]string, s string) []string{
seen[s] = ""
rep := m[s]
var ret []string
var start int = 0
var j int
var ok bool
for i := 0 ; i < len(rep); i++ {
if rep[i] == '`' {
ret = append(ret, rep[start:i])
j = i + lengthOfTypeVar(rep[i: len(rep)])
_, ok = seen[rep[i:j]]
if ok {
fmt.Printf("%s\n", "BOTTOM")
os.Exit(1)
} else {
_, ok = m[rep[i:j]]
if !ok {
ret = append(ret, rep[i:j])
} else {
getBack := typeRelacing(seen, rep[i:j])
for k := 0; k < len(getBack); k++ {
ret = append(ret, getBack[k])
}
}
}
start = j
i = j
}
}
ret = append(ret, rep[start:len(rep)])
return ret
}
func typeUnify(){
var elem string
var ok bool
for i:= 0; i < len(left) ; i++ {
/* BOTH TYPEVAR */
if isValidTypeVar(right[i]) {
/* If they are the same, delete from environment */
if strings.Compare(left[i], right[i]) == 0 {
continue
}
/* Change it into decending order */
if strings.Compare(left[i], right[i]) > 0 {
typeTokenizer(right[i],left[i])
continue
}
}
/* Check Whether have self cycle */
if containType(left[i], right[i]) {
fmt.Printf("%s\n", "BOTTOM")
os.Exit(1)
}
/* Check if it exists */
elem, ok = m[left[i]]
if ok == true {
/* Unify right part */
typeTokenizer(elem, right[i])
} else {
/* Add to MAP */
m[left[i]] = right[i]
}
}
}
func containType(left string, right string) bool{
for i:= 0; i < len(right);i++ {
if right[i] == '`' {
j := i+1
for ;j < len(right); j++ {
if isLetter(right[j]) || isDigit(right[j]) {
continue
}
break
}
if right[i:j] == left {
return true
}
i = j-1
}
}
return false
}
func typeTokenizer(LHS string, RHS string){
var (
i int
tmp_left string
tmp_right string
)
LHS = strings.TrimSpace(LHS)
RHS = strings.TrimSpace(RHS)
/* Primitive always at the right side
VarType always at the left side
FuncType couldn't match ListTyp */
/* TypeVar can Unify with every Type */
/* TypeVar always exist on the left side */
if isValidTypeVar(LHS) {
left = append(left, LHS)
right = append(right, RHS)
} else if isValidTypeVar(RHS) {
left = append(left, RHS)
right = append(right, LHS)
} else if isValidPrimitive(LHS) {
/* Primitive can only Unify with itself */
if LHS != RHS {
fmt.Printf("%s\n", "BOTTOM")
os.Exit(1)
}
} else if isValidFuncType(LHS) {
/* FuncType can only Unify with FuncType */
if !isValidFuncType(RHS) {
fmt.Printf("%s\n", "BOTTOM")
os.Exit(1)
}
/* Split it to Input Part and Output Part */
i = bracketEnd(LHS)
tmp_left = strings.TrimSpace(LHS[0 : i+1])
LHS = strings.TrimSpace(LHS[i+1 : len(LHS)])
LHS = LHS[2: len(LHS)]
i = bracketEnd(RHS)
tmp_right = strings.TrimSpace(RHS[0 : i+1])
RHS = strings.TrimSpace(RHS[i+1 : len(RHS)])
RHS = RHS[2:len(RHS)]
/* Unify output type */
typeTokenizer(LHS, RHS)
/* Remove "(" and ")" */
tmp_left = strings.TrimSpace(tmp_left[1: len(tmp_left)-1])
tmp_right = strings.TrimSpace(tmp_right[1:len(tmp_right)-1])
/* ARGLIST is Empty */
if len(tmp_left) == 0 && len(tmp_right) == 0 {
return
}
/* ARGLIST should not empty */
if len(tmp_left) == 0 || len(tmp_right) == 0 {
fmt.Printf("%s\n", "BOTTOM")
os.Exit(1)
}
/* Split ARGLIST Part */
content_left := argListContent(tmp_left)
content_right := argListContent(tmp_right)
/* ARGLIST Should have same number of Type */
if len(content_left) != len(content_right) {
fmt.Printf("%s\n", "BOTTOM")
os.Exit(1)
}
/* Each part of ARGLIST should be Unified */
for j := 0; j < len(content_left) ; j++ {
typeTokenizer(content_left[j], content_right[j])
}
} else if !isValidList(RHS) {
/* List can be only unified with List */
fmt.Printf("%s\n", "BOTTOM")
os.Exit(1)
} else {
/* Remove "[" and "]", rest should be Unified */
LHS = LHS[1: len(LHS)-1]
RHS = RHS[1: len(RHS)-1]
typeTokenizer(LHS, RHS)
}
}
/* Four kinds of Types */
func isValidType(s string) bool {
s = strings.TrimSpace(s)
if len(s) == 0 {
return false
}
switch s[0:1] {
case "`" : return isValidTypeVar(s)
case "(" : return isValidFuncType(s)
case "[" : return isValidList(s)
default : return isValidPrimitive(s)
}
}
func isValidTypeVar(s string) bool{
/* begin with "`" */
if !strings.HasPrefix(s, "`") {
return false
}
/* At least one letter */
if len(s) < 2 {
return false
}
/* First character should be letter */
if !isLetter(s[1]) {
return false
}
/* Rest Character should be letter or digit */
for i := 2; i < len(s); i++ {
if !isLetter(s[i]) && !isDigit(s[i]) {
return false
}
}
return true
}
func isLetter(ch byte) bool{
if (ch >= 'A') && (ch <= 'Z') {
return true
}
if (ch >= 'a') && (ch <= 'z') {
return true
}
return false
}
func isDigit(ch byte) bool{
if (ch >= '0') && (ch <= '9') {
return true
}
return false
}
func bracketEnd(s string) int{
var stack int = 0
var i int = 0
for ; i < len(s); i++ {
if s[i] == '(' {
stack++
}
if s[i] == ')' {
stack--
}
if stack < 0 {
return -1
}
if stack == 0 {
break
}
}
return i
}
func isValidFuncType(s string) bool{
if !strings.HasPrefix(s, "(") {
return false
}
i := bracketEnd(s)
if i == len(s) || i == -1{
return false
}
/* Character after complete "()" should be "->" */
right_part := strings.TrimSpace(s[i+1: len(s)])
if len(right_part) < 2 || right_part[0:2] != "->" {
return false
}
/* String after "->" should be valid TYPE */
if ! isValidType(right_part[2: len(right_part)]) {
return false
}
s = strings.TrimSpace(s[0:i+1])
return isValidArgList(s[1:len(s)-1])
}
func isValidList(s string) bool{
if !strings.HasPrefix(s, "[") {
return false
}
if !strings.HasSuffix(s, "]") {
return false
}
return isValidType(s[1:len(s)-1])
}
func isValidPrimitive(s string) bool{
if s == "int" || s == "real" || s == "str"{
return true
}
return false
}
/* Split by outside bracket "," */
func argListContent(s string) []string{
var bracket int = 0
var start int = 0
var ret []string
for i:=0 ; i < len(s); i++ {
if s[i] == '(' {
bracket ++
}
if s[i] == ')' {
bracket--
}
if s[i] == ',' && bracket == 0 {
tmp := strings.TrimSpace(s[start:i])
start = i+1
ret = append(ret, tmp)
}
}
ret = append(ret, s[start: len(s)])
return ret
}
func isValidArgList(s string) bool{
s = strings.TrimSpace(s)
if len(s) == 0 {
return true
}
/* Get content of ArgList */
content := argListContent(s)
/* Every Part of ArgList should be Valid TYPE */
for i:= 0; i < len(content);i++ {
if !isValidType(content[i]) {
return false
}
}
return true
}