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Imports System
Imports System.IO
Imports System.Collections.Generic
Imports Mal
Imports MalVal = Mal.types.MalVal
Imports MalInt = Mal.types.MalInt
Imports MalSymbol = Mal.types.MalSymbol
Imports MalList = Mal.types.MalList
Imports MalVector = Mal.types.MalVector
Imports MalHashMap = Mal.types.MalHashMap
Imports MalFunc = Mal.types.MalFunc
Namespace Mal
Class step2_eval
' read
Shared Function READ(str As String) As MalVal
Return reader.read_str(str)
End Function
' eval
Shared Function eval_ast(ast As MalVal, env As Dictionary(Of String, MalVal)) As MalVal
If TypeOf ast Is MalSymbol Then
Dim sym As MalSymbol = DirectCast(ast, MalSymbol)
return env.Item(sym.getName())
Else If TypeOf ast Is MalList Then
Dim old_lst As MalList = DirectCast(ast, MalList)
Dim new_lst As MalList
If ast.list_Q() Then
new_lst = New MalList
Else
new_lst = DirectCast(New MalVector, MalList)
End If
Dim mv As MalVal
For Each mv in old_lst.getValue()
new_lst.conj_BANG(EVAL(mv, env))
Next
return new_lst
Else If TypeOf ast Is MalHashMap Then
Dim new_dict As New Dictionary(Of String, MalVal)
Dim entry As KeyValuePair(Of String, MalVal)
For Each entry in DirectCast(ast,MalHashMap).getValue()
new_dict.Add(entry.Key, EVAL(DirectCast(entry.Value,MalVal), env))
Next
return New MalHashMap(new_dict)
Else
return ast
End If
return ast
End Function
Shared Function EVAL(orig_ast As MalVal, env As Dictionary(Of String, MalVal)) As MalVal
'Console.WriteLine("EVAL: {0}", printer._pr_str(orig_ast, true))
If not orig_ast.list_Q() Then
return eval_ast(orig_ast, env)
End If
' apply list
Dim ast As MalList = DirectCast(orig_ast, MalList)
If ast.size() = 0 Then
return ast
End If
Dim a0 As MalVal = ast(0)
Dim el As MalList = DirectCast(eval_ast(ast, env), MalList)
Dim f As MalFunc = DirectCast(el(0), MalFunc)
Return f.apply(el.rest())
End Function
' print
Shared Function PRINT(exp As MalVal) As String
return printer._pr_str(exp, TRUE)
End Function
' repl
Shared repl_env As Dictionary(Of String, MalVal)
Shared Function REP(str As String) As String
Return PRINT(EVAL(READ(str), repl_env))
End Function
Shared Function add(a As MalList) As MalVal
Return DirectCast(a.Item(0),MalInt) + DirectCast(a.Item(1),MalInt)
End Function
Shared Function minus(a As MalList) As MalVal
Return DirectCast(a.Item(0),MalInt) - DirectCast(a.Item(1),MalInt)
End Function
Shared Function mult(a As MalList) As MalVal
Return DirectCast(a.Item(0),MalInt) * DirectCast(a.Item(1),MalInt)
End Function
Shared Function div(a As MalList) As MalVal
Return DirectCast(a.Item(0),MalInt) / DirectCast(a.Item(1),MalInt)
End Function
Shared Function Main As Integer
Dim args As String() = Environment.GetCommandLineArgs()
repl_env = New Dictionary(Of String, MalVal)
repl_env.Add("+", New MalFunc(AddressOf add))
repl_env.Add("-", New MalFunc(AddressOf minus))
repl_env.Add("*", New MalFunc(AddressOf mult))
repl_env.Add("/", New MalFunc(AddressOf div))
If args.Length > 1 AndAlso args(1) = "--raw" Then
Mal.readline.SetMode(Mal.readline.Modes.Raw)
End If
' repl loop
Dim line As String
Do
Try
line = Mal.readline.Readline("user> ")
If line is Nothing Then
Exit Do
End If
If line = "" Then
Continue Do
End If
Catch e As IOException
Console.WriteLine("IOException: " & e.Message)
End Try
Try
Console.WriteLine(REP(line))
Catch e as Exception
Console.WriteLine("Error: " & e.Message)
Console.WriteLine(e.StackTrace)
Continue Do
End Try
Loop While True
End function
End Class
End Namespace
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