-
Notifications
You must be signed in to change notification settings - Fork 0
/
statement.scala
165 lines (152 loc) · 6.34 KB
/
statement.scala
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
import java.io.File
import scala.io.Source
enum Token:
case Value extends Token
case Operator extends Token
case Keyword extends Token
sealed trait Term(token: Token)
object Term:
import Token.*
case object Show extends Term(Keyword)
case object Hide extends Term(Keyword)
case object Set extends Term(Keyword)
case object When extends Term(Keyword)
case object Or extends Term(Keyword)
case object And extends Term(Keyword)
case object To extends Term(Keyword)
case object Eq extends Term(Operator)
case class Val(content: String) extends Term(Token.Value)
case class Pointer(binding: String) extends Term(Token.Value)
case class Statement(terms: List[Term])
sealed trait Expr
object Expr:
case object Nop extends Expr
case class Value(value: String) extends Expr
case class Error(value: String) extends Expr
case class Pointer(binding: String) extends Expr
case class Predicate(expr: Expr, check: Expr) extends Expr
case class Or(left: Expr, right: Expr) extends Expr
case class And(left: Expr, right: Expr) extends Expr
case class Eq(left: Expr, right: Expr) extends Expr
case class Assignment(receiver: Pointer, value: Expr) extends Expr
case class Show(value: Expr) extends Expr
case class Hide(value: Expr) extends Expr
object Parser:
import Term.*
def parseTerms(source: String): List[Term] = source.split(" ").toList.map {
case "Show" => Show
case "Hide" => Hide
case "Set" => Set
case "when" => When
case "or" => Or
case "and" => And
case "to" => To
case "==" => Eq
case token if token.startsWith("*") => Pointer(token.drop(1))
case token => Val(token)
}
def parse(statements: List[String]): List[Statement] =
statements.map(terms => Statement(parseTerms(terms)))
def read(file: File): List[String] =
Source.fromFile(file, "UTF-8").getLines().toList
object AST:
import Term.*
def toAST(
terms: List[Term],
current: Expr = Expr.Nop,
stack: List[Term] = List.empty
): Expr =
if terms.isEmpty then current
else
terms.head match
case Show => toAST(terms.tail, current, stack :+ Term.Show)
case Hide => toAST(terms.tail, current, stack :+ Term.Hide)
case Set => toAST(terms.tail, current, stack :+ Term.Set)
case When => Expr.Predicate(current, toAST(terms.tail, Expr.Nop, stack))
case Or => Expr.Or(current, toAST(terms.tail, stack = stack))
case And => Expr.And(current, toAST(terms.tail, stack = stack))
case To =>
stack match
case Set :: Pointer(binding) :: _ =>
toAST(terms.tail, stack = stack :+ To)
case _ => Expr.Error("'to' is expected")
case Eq => toAST(terms.tail, current, stack :+ Eq)
case Val(content) =>
stack match
case Set :: Pointer(binding) :: To :: _ =>
toAST(
terms.tail,
Expr.Assignment(Expr.Pointer(binding), Expr.Value(content)),
stack.drop(3)
)
case Eq :: _ =>
toAST(
terms.tail,
Expr.Eq(current, Expr.Value(content)),
stack.drop(1)
)
case _ => toAST(terms.tail, Expr.Value(content), stack)
case Pointer(binding) =>
stack.head match
case Show =>
toAST(terms.tail, Expr.Show(Expr.Pointer(binding)), stack.init)
case Hide =>
toAST(terms.tail, Expr.Hide(Expr.Pointer(binding)), stack.init)
case Set =>
toAST(terms.tail, stack = stack :+ Pointer(binding))
case _ => Expr.Nop
object Interpreter:
import Expr.*
def asString(root: Expr): String =
root match
case Nop => "NOP"
case Value(value) => s"$value"
case Pointer(binding) => s"*$binding"
case Predicate(expr, check) =>
s"if ${asString(check)} then ${asString(expr)}"
case Or(left, right) => s"(${asString(left)} or ${asString(right)})"
case And(left, right) => s"(${asString(left)} and ${asString(right)})"
case Eq(left, right) => s"${asString(left)} == ${asString(right)}"
case Assignment(receiver, value) =>
s"${asString(receiver)} = ${asString(value)}"
case Show(value) => s"Show ${asString(value)}"
case Hide(value) => s"Hide ${asString(value)}"
def asGraphVis(root: Expr, level: Int = 0, parent: String = "ROOT"): String =
root match
case Nop => s"$parent -- NOP\n"
case Value(value) => s"$parent -- \"$value\"\n"
case Pointer(binding) => s"$parent -- \"*($binding)\"\n"
case Predicate(expr, check) =>
s"PREDICATE$level [label=\"PREDICATE\"]\n" +
s"$parent -- PREDICATE$level\n" +
asGraphVis(check, level + 1, s"PREDICATE$level") +
asGraphVis(expr, level + 2, s"PREDICATE$level")
case Or(left, right) =>
s"OR$level [label=\"OR\"]\n" +
s"$parent -- OR$level\n" +
asGraphVis(left, level + 1, s"OR$level") +
asGraphVis(right, level + 2, s"OR$level")
case And(left, right) =>
s"AND$level [label=\"AND\"]\n" +
s"$parent -- AND$level\n" +
asGraphVis(left, level + 1, s"AND$level") +
asGraphVis(right, level + 2, s"AND$level")
case Eq(left, right) =>
s"EQ$level [label=\"EQ\"]\n" +
s"$parent -- EQ$level\n" +
asGraphVis(left, level + 1, s"EQ$level") +
asGraphVis(right, level + 2, s"EQ$level")
case Assignment(receiver, value) =>
s"ASSIGNMENT$level [label=\"ASSIGNMENT\"]\n" +
s"$parent -- ASSIGNMENT$level\n" +
asGraphVis(receiver, level + 1, s"ASSIGNMENT$level") +
asGraphVis(value, level + 2, s"ASSIGNMENT$level")
case Show(value) => s"$parent -- \"SHOW$level ($value)\"\n"
case Hide(value) => s"$parent -- \"HIDE$level ($value)\"\n"
@main def entrypoint =
val statements = Parser.parse(read(File("example.txt")))
val ast = statements.map(statement => AST.toAST(statement.terms))
statements.foreach(println)
ast.foreach(println)
ast.foreach(root => println(Interpreter.asString(root)))
ast.foreach(root => println(Interpreter.asGraphVis(root)))