From a630029b6cd4a1e61025f6c0a40e198b90802946 Mon Sep 17 00:00:00 2001
From: Ryo Nihei <nihei.dev@gmail.com>
Date: Sun, 12 Dec 2021 18:03:06 +0900
Subject: Remove --lex-spec option from maleeni-compile command

---
 README.md              |  2 +-
 cmd/maleeni/compile.go | 14 ++++++++++----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 9c9d4df..805e50c 100644
--- a/README.md
+++ b/README.md
@@ -51,7 +51,7 @@ Save the above specification to a file in UTF-8. In this explanation, the file n
 Next, generate a DFA from the lexical specification using `maleeni compile` command.
 
 ```sh
-$ maleeni compile -l statement.json -o statementc.json
+$ maleeni compile statement.json -o statementc.json
 ```
 
 ### 3. Debug (Optional)
diff --git a/cmd/maleeni/compile.go b/cmd/maleeni/compile.go
index 21e5058..2fcb8ad 100644
--- a/cmd/maleeni/compile.go
+++ b/cmd/maleeni/compile.go
@@ -15,7 +15,6 @@ import (
 
 var compileFlags = struct {
 	debug   *bool
-	lexSpec *string
 	compLv  *int
 	output  *string
 }{}
@@ -25,17 +24,24 @@ func init() {
 		Use:     "compile",
 		Short:   "Compile a lexical specification into a DFA",
 		Long:    `compile takes a lexical specification and generates a DFA accepting the tokens described in the specification.`,
-		Example: `  cat lexspec.json | maleeni compile > clexspec.json`,
+		Example: `  Read from/Write to the specified file:
+    maleeni compile lexspec.json -o clexspec.json
+  Read from stdin and write to stdout:
+    cat lexspec.json | maleeni compile`,
+		Args:    cobra.MaximumNArgs(1),
 		RunE:    runCompile,
 	}
-	compileFlags.lexSpec = cmd.Flags().StringP("lex-spec", "l", "", "lexical specification file path (default stdin)")
 	compileFlags.compLv = cmd.Flags().Int("compression-level", compiler.CompressionLevelMax, "compression level")
 	compileFlags.output = cmd.Flags().StringP("output", "o", "", "output file path (default stdout)")
 	rootCmd.AddCommand(cmd)
 }
 
 func runCompile(cmd *cobra.Command, args []string) (retErr error) {
-	lspec, err := readLexSpec(*compileFlags.lexSpec)
+	var path string
+	if len(args) > 0 {
+		path = args[0]
+	}
+	lspec, err := readLexSpec(path)
 	if err != nil {
 		return fmt.Errorf("Cannot read a lexical specification: %w", err)
 	}
-- 
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