Allow negation directly after a binary operator.

This should address #294.

Author: 01mf02

jaq-core/src/load/lex.rs

@@ -291,15 +291,16 @@ impl<'a> Lexer<&'a str> {
     fn token(&mut self) -> Option<Token<&'a str>> {
         self.space();
 
-        let is_op = |c| "|=!<>+-*/%".contains(c);
+        let hd_op = |c| "|=!<>+-*/%".contains(c);
+        let tl_op = |c| hd_op(c) && c != '-';
 
         let mut chars = self.i.chars();
         let (s, tok) = match chars.next()? {
             'a'..='z' | 'A'..='Z' | '_' => (self.consumed(1, Self::mod_then_ident), Tok::Word),
             '$' => (self.consumed(1, Self::ident1), Tok::Var),
             '@' => (self.consumed(1, Self::ident1), Tok::Fmt),
             '0'..='9' => (self.consumed(1, Self::num), Tok::Num),
-            c if is_op(c) => (self.consumed(1, |lex| lex.trim(is_op)), Tok::Sym),
+            c if hd_op(c) => (self.consumed(1, |lex| lex.trim(tl_op)), Tok::Sym),
             '.' => match chars.next() {
                 Some('.') => (self.take(2), Tok::Sym),
                 Some('a'..='z' | 'A'..='Z' | '_') => (self.consumed(2, Self::ident0), Tok::Sym),

jaq-core/tests/tests.rs

@@ -141,6 +141,8 @@ yields!(atomic_opt, "def x: 0; try x? catch 1", 0);
 yields!(neg_arr_iter1, "[-[][]]", json!([]));
 yields!(neg_arr_iter2, "try (-[])[] catch 0", 0);
 
+yields!(neg_after_bin, ".+=-1", -1);
+
 yields!(interpolation, r#"1 | "yields \(.+1)!""#, "yields 2!");
 // this diverges from jq, which yields ["2 2", "3 2", "2 4", "3 4"],
 // probably due to different order of evaluation addition