More robust argument parsing

1 files changed, 11 insertions, 5 deletions

diff --git a/src/main.rs b/src/main.rs
index 8c74322..a96f1a5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -9,11 +9,11 @@ use std::process;
 pub mod args;
 
 use rand::{thread_rng, seq::{SliceRandom, IteratorRandom}};
-use crate::args::Args;
+use crate::args::{Args, ArgError, HELP_STR};
 
 #[derive(Debug)]
 enum Error {
-    BadArguments,
+    BadArguments(ArgError),
     NoSentences,
     MultipleSentences,
     BadTemplate(String),
@@ -30,8 +30,8 @@ enum Error {
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            Error::BadArguments =>
-                write!(f, "error while parsing arguments"),
+            Error::BadArguments(e) =>
+                write!(f, "Error while parsing arguments: {}\n{}", e, HELP_STR),
             Error::NoSentences =>
                 write!(f, "no sentences.txt file found"),
             Error::MultipleSentences =>
@@ -64,6 +64,12 @@ impl From<io::Error> for Error {
     }
 }
 
+impl From<ArgError> for Error {
+    fn from(error: ArgError) -> Self {
+        Error::BadArguments(error)
+    }
+}
+
 type ProgResult<T> = Result<T, Error>;
 
 #[derive(Debug, Clone)]
@@ -316,7 +322,7 @@ fn crash(e: Error) -> ! {
 }
 
 fn sub_main() -> ProgResult<()> {
-    let args = Args::parse().ok_or(Error::BadArguments)?;
+    let args = Args::parse()?;
     let (mut sentences, mut categories) = read_files(&args.directory, args.unique)?;
 
     for _i in 0..args.n_sentences {