alpha, digit and others should not accept empty input

src/nom.rs

@@ -91,7 +91,11 @@ use std::ops::{Index,Range,RangeFrom};
 /// Recognizes lowercase and uppercase alphabetic characters: a-zA-Z
 pub fn alpha<'a, T: ?Sized>(input:&'a T) -> IResult<&'a T, &'a T> where
     T:Index<Range<usize>, Output=T>+Index<RangeFrom<usize>, Output=T>,
-    &'a T: IterIndices {
+    &'a T: IterIndices+InputLength {
+  if input.input_len() == 0 {
+    return Error(Position(ErrorKind::Alpha, input))
+  }
+
   for (idx, item) in input.iter_indices() {
     if ! item.is_alpha() {
       if idx == 0 {
@@ -107,7 +111,11 @@ pub fn alpha<'a, T: ?Sized>(input:&'a T) -> IResult<&'a T, &'a T> where
 /// Recognizes numerical characters: 0-9
 pub fn digit<'a, T: ?Sized>(input:&'a T) -> IResult<&'a T, &'a T> where
     T:Index<Range<usize>, Output=T>+Index<RangeFrom<usize>, Output=T>,
-    &'a T: IterIndices {
+    &'a T: IterIndices+InputLength {
+  if input.input_len() == 0 {
+    return Error(Position(ErrorKind::Digit, input))
+  }
+
   for (idx, item) in input.iter_indices() {
     if ! item.is_0_to_9() {
       if idx == 0 {
@@ -123,7 +131,11 @@ pub fn digit<'a, T: ?Sized>(input:&'a T) -> IResult<&'a T, &'a T> where
 /// Recognizes numerical and alphabetic characters: 0-9a-zA-Z
 pub fn alphanumeric<'a, T: ?Sized>(input:&'a T) -> IResult<&'a T, &'a T> where
     T:Index<Range<usize>, Output=T>+Index<RangeFrom<usize>, Output=T>,
-    &'a T: IterIndices {
+    &'a T: IterIndices+InputLength {
+  if input.input_len() == 0 {
+    return Error(Position(ErrorKind::AlphaNumeric, input));
+  }
+
   for (idx, item) in input.iter_indices() {
     if ! item.is_alphanum() {
       if idx == 0 {
@@ -139,7 +151,11 @@ pub fn alphanumeric<'a, T: ?Sized>(input:&'a T) -> IResult<&'a T, &'a T> where
 /// Recognizes spaces and tabs
 pub fn space<'a, T: ?Sized>(input:&'a T) -> IResult<&'a T, &'a T> where
     T:Index<Range<usize>, Output=T>+Index<RangeFrom<usize>, Output=T>,
-    &'a T: IterIndices {
+    &'a T: IterIndices+InputLength {
+  if input.input_len() == 0 {
+    return Error(Position(ErrorKind::Space, input));
+  }
+
   for (idx, item) in input.iter_indices() {
     let chr = item.as_char();
     if ! (chr == ' ' || chr == '\t')  {
@@ -156,7 +172,11 @@ pub fn space<'a, T: ?Sized>(input:&'a T) -> IResult<&'a T, &'a T> where
 /// Recognizes spaces, tabs, carriage returns and line feeds
 pub fn multispace<'a, T: ?Sized>(input:&'a T) -> IResult<&'a T, &'a T> where
     T:Index<Range<usize>, Output=T>+Index<RangeFrom<usize>, Output=T>,
-    &'a T: IterIndices {
+    &'a T: IterIndices+InputLength {
+  if input.input_len() == 0 {
+    return Error(Position(ErrorKind::MultiSpace, input));
+  }
+
   for (idx, item) in input.iter_indices() {
     let chr = item.as_char();
     if ! (chr == ' ' || chr == '\t' || chr == '\r' || chr == '\n')  {

tests/issues.rs

@@ -1,7 +1,8 @@
 #[macro_use]
 extern crate nom;
 
-use nom::{IResult,Needed};
+use nom::{IResult,Needed,HexDisplay,space,digit};
+use std::str;
 
 #[allow(dead_code)]
 struct Range {
@@ -63,3 +64,34 @@ fn issue_58() {
 }
 
 //trace_macros!(false);
+
+named!(parse_ints< Vec<i32> >, many0!(spaces_or_int));
+
+fn spaces_or_int(input: &[u8]) -> IResult<&[u8], i32>{
+  println!("{}", input.to_hex(8));
+  chain!(input,
+    opt!(space) ~
+    x:   digit,
+    || {
+      println!("x: {:?}", x);
+      let result = str::from_utf8(x).unwrap();
+      println!("Result: {}", result);
+      println!("int is empty?: {}", x.is_empty());
+      match result.parse(){
+        Ok(i) => i,
+        Err(_) =>  panic!("UH OH! NOT A DIGIT!")
+      }
+    }
+  )
+}
+
+#[test]
+fn issue_142(){
+   let subject = parse_ints(&b"12 34 5689"[..]);
+   let expected = IResult::Done(&b""[..], vec![12, 34, 5689]);
+   assert_eq!(subject, expected);
+
+   let subject = parse_ints(&b"12 34 5689 "[..]);
+   let expected = IResult::Done(&b" "[..], vec![12, 34, 5689]);
+   assert_eq!(subject, expected)
+}