..
Viewing
repl.go
62 lines (51 loc) • 1.6 KB
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 | package repl
import (
"bufio"
"fmt"
"io"
"mana/evaluator"
"mana/lexer"
"mana/object"
"mana/parser"
)
// PROMPT is the prompt for the REPL.
const PROMPT = ">>> "
const MANA_START = `
███╗░░░███╗░█████╗░███╗░░██╗░█████╗░
████╗░████║██╔══██╗████╗░██║██╔══██╗
██╔████╔██║███████║██╔██╗██║███████║
██║╚██╔╝██║██╔══██║██║╚████║██╔══██║
██║░╚═╝░██║██║░░██║██║░╚███║██║░░██║
╚═╝░░░░░╚═╝╚═╝░░╚═╝╚═╝░░╚══╝╚═╝░░╚═╝
`
func Start(in io.Reader, out io.Writer) {
var scanner *bufio.Scanner = bufio.NewScanner(in)
env := object.NewEnvironment()
io.WriteString(out, MANA_START+"\n")
for {
fmt.Fprint(out, PROMPT)
var scanned bool = scanner.Scan()
if !scanned {
return
}
var line string = scanner.Text()
var l *lexer.Lexer = lexer.New(line)
var p *parser.Parser = parser.New(l)
var program = p.ParseProgram()
if len(p.Errors()) != 0 {
printParserErrors(out, p.Errors())
continue
}
evaluated := evaluator.Eval(program, env)
if evaluated != nil {
io.WriteString(out, evaluated.Inspect())
io.WriteString(out, "\n")
}
}
}
func printParserErrors(out io.Writer, errors []string) {
io.WriteString(out, "ParseError:\n")
for _, msg := range errors {
io.WriteString(out, "\t"+msg+"\n")
}
}
|
|