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path: root/ethereum/repl_darwin.go
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package main

// #cgo LDFLAGS: -lreadline
// #include <stdio.h>
// #include <stdlib.h>
// #include <readline/readline.h>
// #include <readline/history.h>
import "C"

import (
    "strings"
    "unsafe"
)

func readLine(prompt *string) *string {
    var p *C.char

    //readline allows an empty prompt(NULL)
    if prompt != nil {
        p = C.CString(*prompt)
    }

    ret := C.readline(p)

    if p != nil {
        C.free(unsafe.Pointer(p))
    }

    if ret == nil {
        return nil
    } //EOF

    s := C.GoString(ret)
    C.free(unsafe.Pointer(ret))
    return &s
}

func addHistory(s string) {
    p := C.CString(s)
    C.add_history(p)
    C.free(unsafe.Pointer(p))
}

var indentCount = 0
var str = ""

func (self *JSRepl) setIndent() {
    open := strings.Count(str, "{")
    open += strings.Count(str, "(")
    closed := strings.Count(str, "}")
    closed += strings.Count(str, ")")
    indentCount = open - closed
    if indentCount <= 0 {
        self.prompt = "> "
    } else {
        self.prompt = strings.Join(make([]string, indentCount*2), "..")
        self.prompt += " "
    }
}

func (self *JSRepl) read() {
L:
    for {
        switch result := readLine(&self.prompt); true {
        case result == nil:
            break L //exit loop

        case *result != "": //ignore blank lines
            str += *result + "\n"

            self.setIndent()

            if indentCount <= 0 {
                addHistory(str) //allow user to recall this line

                self.parseInput(str)
            }
        }
    }
}