underscore issue on parse_str

common/Cargo.toml

@@ -13,8 +13,8 @@ parking_lot = { version = "0.11.0", optional = true }
 num-traits = "0.2"
 num-complex = "0.4.0"
 num-bigint = "0.4.2"
-lexical-core = "0.7"
-hexf-parse = "0.1.0"
+lexical-parse-float = { version = "0.8.0", features = ["format"] }
+hexf-parse = "0.2.1"
 cfg-if = "1.0"
 once_cell = "1.4.1"
 siphasher = "0.3"

common/src/float_ops.rs

@@ -64,36 +64,32 @@ pub fn gt_int(value: f64, other_int: &BigInt) -> bool {
 }
 
 pub fn parse_str(literal: &str) -> Option<f64> {
-    if literal.starts_with('_') || literal.ends_with('_') {
-        return None;
-    }
-
-    let mut buf = String::with_capacity(literal.len());
-    let mut last_tok: Option<char> = None;
-    for c in literal.chars() {
-        if !(c.is_ascii_alphanumeric() || c == '_' || c == '+' || c == '-' || c == '.') {
-            return None;
-        }
+    parse_inner(literal.trim().as_bytes())
+}
 
-        if !c.is_ascii_alphanumeric() {
-            if let Some(l) = last_tok {
-                if !l.is_ascii_alphanumeric() && !(c == '.' && (l == '-' || l == '+')) {
-                    return None;
-                }
-            }
-        }
+pub fn parse_bytes(literal: &[u8]) -> Option<f64> {
+    parse_inner(trim_slice(literal, |b| b.is_ascii_whitespace()))
+}
 
-        if c != '_' {
-            buf.push(c);
-        }
-        last_tok = Some(c);
+fn trim_slice<T>(v: &[T], mut trim: impl FnMut(&T) -> bool) -> &[T] {
+    let mut it = v.iter();
+    while it.clone().next().map_or(false, &mut trim) {
+        it.next();
     }
-
-    if let Ok(f) = lexical_core::parse(buf.as_bytes()) {
-        Some(f)
-    } else {
-        None
+    while it.clone().next_back().map_or(false, &mut trim) {
+        it.next_back();
     }
+    it.as_slice()
+}
+
+fn parse_inner(literal: &[u8]) -> Option<f64> {
+    use lexical_parse_float::{
+        format::PYTHON3_LITERAL, FromLexicalWithOptions, NumberFormatBuilder, Options, 
+    };
+    const PYTHON_STRING: u128 = NumberFormatBuilder::rebuild(PYTHON3_LITERAL)
+        .no_special(false)
+        .build();
+    f64::from_lexical_with_options::<PYTHON_STRING>(literal, &Options::new()).ok()
 }
 
 pub fn is_integer(v: f64) -> bool {
@@ -495,3 +491,9 @@ fn test_remove_trailing_redundant_chars() {
     // don't truncate integers
     assert!(remove_trailing_redundant_chars(String::from("1000")) == String::from("1000"));
 }
+
+#[test]
+fn test_parse_str(){
+    assert!(parse_str("1e1") == Some(10.0));
+    assert!(parse_str("1_e1") == None);
+}