87 lines
1.8 KiB
Go
87 lines
1.8 KiB
Go
package repl
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import (
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"bufio"
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"fmt"
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"io"
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"monkey/compiler"
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"monkey/lexer"
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"monkey/object"
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"monkey/parser"
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"monkey/vm"
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)
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const PROMPT = ">> "
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func Start(in io.Reader, out io.Writer) {
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scanner := bufio.NewScanner(in)
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constants := []object.Object{}
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globals := make([]object.Object, vm.GlobalsSize)
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symbolTable := compiler.NewSymbolTable()
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for i, v := range object.Builtins {
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symbolTable.DefineBuiltin(i, v.Name)
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}
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for {
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fmt.Fprintf(out, PROMPT)
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scanned := scanner.Scan()
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if !scanned {
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return
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}
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line := scanner.Text()
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l := lexer.New(line)
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p := parser.New(l)
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program := p.ParseProgram()
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if len(p.Errors()) != 0 {
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printParserErrors(out, p.Errors())
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continue
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}
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comp := compiler.NewWithState(symbolTable, constants)
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err := comp.Compile(program)
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if err != nil {
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fmt.Fprintf(out, "Woops! Compilation failed:\n %s\n", err)
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continue
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}
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code := comp.Bytecode()
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constants = code.Constants
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machine := vm.NewWithGlobalState(comp.Bytecode(), globals)
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err = machine.Run()
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if err != nil {
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fmt.Fprintf(out, "Woops! Executing bytecode failed:\n %s\n", err)
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continue
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}
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stackTop := machine.LastPoppedStackElem()
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io.WriteString(out, stackTop.Inspect())
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io.WriteString(out, "\n")
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}
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}
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const MONKEY_FACE = ` __,__
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.--. .-" "-. .--.
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/ .. \/ .-. .-. \/ .. \
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| | '| / Y \ |' | |
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| \ \ \ 0 | 0 / / / |
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\ '- ,\.-"""""""-./, -' /
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''-' /_ ^ ^ _\ '-''
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| \._ _./ |
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\ \ '~' / /
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'._ '-=-' _.'
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'-----'
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`
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func printParserErrors(out io.Writer, errors []string) {
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io.WriteString(out, MONKEY_FACE)
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io.WriteString(out, "Woops! We ran into some monkey business here!\n")
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io.WriteString(out, " parser errors:\n")
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for _, msg := range errors {
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io.WriteString(out, "\t"+msg+"\t")
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}
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}
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