/
main.go
96 lines (78 loc) · 1.63 KB
/
main.go
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package main
import (
"fmt"
logpkg "log"
"os"
)
import (
"github.com/timtadh/getopt"
)
import (
"github.com/timtadh/lexmachine/frontend"
)
var log *logpkg.Logger
func init() {
log = logpkg.New(os.Stderr, "", 0)
}
var usageMessage = "lexc -p <pattern> [-p <pattern>]*"
var extendedMessage = `
lexc compiles regular expressions to a program suitable for lexing
Options
-h, --help print this message
-p, --pattern=<pattern> a regex pattern
Specs
<pattern>
a regex pattern
`
func usage(code int) {
fmt.Fprintln(os.Stderr, usageMessage)
if code == 0 {
fmt.Fprintln(os.Stderr, extendedMessage)
code = 1
} else {
fmt.Fprintln(os.Stderr, "Try -h or --help for help")
}
os.Exit(code)
}
func main() {
short := "hp:"
long := []string{
"help",
"pattern=",
}
_, optargs, err := getopt.GetOpt(os.Args[1:], short, long)
if err != nil {
log.Print(err)
usage(1)
}
patterns := make([]string, 0, 10)
for _, oa := range optargs {
switch oa.Opt() {
case "-h", "--help":
usage(0)
case "-p", "--pattern":
patterns = append(patterns, oa.Arg())
}
}
if len(patterns) <= 0 {
log.Print("Must supply some regulars expressions!")
usage(1)
}
asts := make([]frontend.AST, 0, len(patterns))
for _, p := range patterns {
ast, err := frontend.Parse([]byte(p))
if err != nil {
log.Fatal(err)
}
asts = append(asts, ast)
}
lexast := asts[len(asts)-1]
for i := len(asts) - 2; i >= 0; i-- {
lexast = frontend.NewAltMatch(asts[i], lexast)
}
program, err := frontend.Generate(lexast)
if err != nil {
log.Fatal(err)
}
fmt.Println(program.Serialize())
}