refactor/polish ~ fix cargo clippy complaints (while let ... = some => for ... in)

src/od/parse_formats.rs

@@ -107,7 +107,7 @@ pub fn parse_format_flags(args: &Vec<String>) -> Result<Vec<ParsedFormatterItemI
     let mut arg_iter = args.iter().skip(1);
     let mut expect_type_string = false;
 
-    while let Some(arg) = arg_iter.next() {
+    for arg in arg_iter {
         if expect_type_string {
             match parse_type_string(arg) {
                 Ok(v) => formats.extend(v.into_iter()),
@@ -131,7 +131,7 @@ pub fn parse_format_flags(args: &Vec<String>) -> Result<Vec<ParsedFormatterItemI
         } else if arg.starts_with("-") {
             let mut flags = arg.chars().skip(1);
             let mut format_spec = String::new();
-            while let Some(c) = flags.next() {
+            for c in flags {
                 if expect_type_string {
                     format_spec.push(c);
                 } else if od_argument_with_option(c) {

src/printf/tokenize/num_format/formatters/float_common.rs

@@ -62,7 +62,7 @@ impl FloatAnalysis {
         };
         let mut i = 0;
         let mut pos_before_first_nonzero_after_decimal: Option<usize> = None;
-        while let Some(c) = str_it.next() {
+        for c in str_it {
             match c {
                 e @ '0'..='9' | e @ 'A'..='F' | e @ 'a'..='f' => {
                     if !hex_input {
@@ -255,7 +255,7 @@ pub fn get_primitive_dec(
                     let mut m: isize = 0;
                     let mut pre = String::from("0");
                     let mut post = String::from("0");
-                    while let Some((i, c)) = it.next() {
+                    for (i, c) in it {
                         match c {
                             '0' => {}
                             _ => {

src/printf/tokenize/num_format/num_format.rs

@@ -49,7 +49,7 @@ fn get_provided(str_in_opt: Option<&String>) -> Option<u8> {
                         return Some(match byte_it.next() {
                             Some(second_byte) => {
                                 let mut ignored: Vec<u8> = Vec::new();
-                                while let Some(cont) = byte_it.next() {
+                                for cont in byte_it {
                                     ignored.push(cont);
                                 }
                                 if ignored.len() > 0 {
@@ -159,7 +159,7 @@ fn get_inprefix(str_in: &str, field_type: &FieldType) -> InPrefix {
             }
             if do_clean_lead_zeroes {
                 let mut first = true;
-                while let Some(ch_zero) = str_it.next() {
+                for ch_zero in str_it {
                     // see notes on offset above:
                     // this is why the offset for octals and decimals
                     // that reach this branch is 1 even though

src/printf/tokenize/sub.rs

@@ -177,7 +177,7 @@ impl SubParser {
 
         // divide substitution from %([0-9]+)?(.[0-9+])?([a-zA-Z])
         // into min_width, second_field, field_char
-        while let Some(ch) = it.next() {
+        for ch in it {
             self.text_so_far.push(ch);
             match ch as char {
                 '-' | '*' | '0'..='9' => {

src/stat/stat.rs

@@ -136,7 +136,7 @@ impl ScanUtil for str {
             Some('-') | Some('+') | Some('0'..='9') => i += 1,
             _ => return None,
         }
-        while let Some(c) = chars.next() {
+        for c in chars {
             match c {
                 '0'..='9' => i += 1,
                 _ => break,
@@ -155,10 +155,10 @@ impl ScanUtil for str {
             16 => 2,
             _ => return None,
         };
-        let mut chars = self.chars().enumerate();
+        let chars = self.chars().enumerate();
         let mut res = 0_u32;
         let mut offset = 0_usize;
-        while let Some((i, c)) = chars.next() {
+        for (i, c) in chars {
             if i >= count {
                 break;
             }