feat: began work on preprocessor

fleck.go

@@ -5,6 +5,7 @@ import (
 	"os"
 
 	"github.com/xnacly/fleck/cli"
+	"github.com/xnacly/fleck/preprocessor"
 	"github.com/xnacly/fleck/scanner"
 )
 
@@ -18,6 +19,14 @@ func main() {
 		os.Exit(1)
 	}
 
-	s := scanner.New(ARGUMENTS.InputFile)
+	if ARGUMENTS.ShellMacroEnabled {
+		log.Println("warning: 'shell-macro-enabled' flag specified, this can harm your operating system and make it vulnerable for attack, proceed at your own digression")
+	}
+
+	fileName := ARGUMENTS.InputFile
+
+	preprocessor.Process(fileName)
+
+	s := scanner.New(fileName + ".fleck")
 	s.Lex()
 }

preprocessor/preprocessor.go

@@ -1,6 +1,35 @@
 package preprocessor
 
-// this module contains logic for replacing snippets / macros in the future, such as:
-// - @include{file} => gets replaced with the markdown content of the file
-// - @today{format} => gets replaced by the current date
-// - @shell{command} => gets replaced by the output of the given command
+// possible errors:
+// - empty @include => warning
+// - @include cycle => error and abort
+// - empty @today => warning
+// - empty @shell => warning
+
+import (
+	"bufio"
+	"log"
+	"os"
+	"time"
+)
+
+func Process(filename string) {
+	f, err := os.Open(filename)
+	if err != nil {
+		log.Fatalln("couldn't open file: '" + err.Error() + "'")
+	}
+	s := bufio.NewScanner(f)
+
+	ok := s.Scan()
+	for ok {
+		s.Text()
+		// process the line here, replace found macros
+		ok = s.Scan()
+	}
+
+	// write to filename+".fleck" here
+}
+
+func todayMacro(format string) string {
+	return time.Now().Format(format)
+}

scanner/scanner.go

@@ -24,7 +24,7 @@ type Scanner struct {
 func New(fileName string) Scanner {
 	file, err := os.Open(fileName)
 	if err != nil {
-		log.Fatalln("couldn't open file", err)
+		log.Fatalln("couldn't open file: '" + err.Error() + "'")
 	}
 	scan := bufio.NewScanner(file)
 	scan.Scan()