Make the lexer accept scientific notation (#1456)

* Make the lexer accept scientific notation * Mention scientific notation on doc/manual/syntax.md
tweag · Jul 17, 2023 · da07e3e · da07e3e
1 parent 3d47bac
commit da07e3e
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Showing 3 changed files with 15 additions and 3 deletions.
diff --git a/core/src/parser/lexer.rs b/core/src/parser/lexer.rs
@@ -69,7 +69,7 @@ pub enum NormalToken<'input> {
     // regex for checking identifiers at ../lsp/nls/src/requests/completion.rs
     #[regex("_?[a-zA-Z][_a-zA-Z0-9-']*")]
     Identifier(&'input str),
-    #[regex("[0-9]*\\.?[0-9]+", |lex| parse_number(lex.slice()))]
+    #[regex("[0-9]*\\.?[0-9]+([eE][+\\-]?[0-9]+)?", |lex| parse_number(lex.slice()))]
     NumLiteral(Number),
 
     // **IMPORTANT**

diff --git a/core/tests/integration/pass/core/numbers.ncl b/core/tests/integration/pass/core/numbers.ncl
@@ -0,0 +1,10 @@
+# test.type = 'pass'
+let {check, ..} = import "../lib/assert.ncl" in
+
+[
+  5 + 5 == 10,
+  5 * 5 == 25,
+  1e6 == 1000000,
+  1e+3 / 2e-3 == 0.5e6,
+]
+|> check
diff --git a/doc/manual/syntax.md b/doc/manual/syntax.md
@@ -39,12 +39,14 @@ fit exactly into a 64-bit signed integer or a 64-bit unsigned integer. They
 are serialized as a 64-bit float otherwise. The latter conversion might lose
 precision as well, for example when serializing `1/3`.
 
-Here are some examples of number literals in Nickel:
+Here are some examples of number literals in Nickel; scientific notation for
+decimal is supported:
 
 ```nickel
 1
 0.543
-42
+1.7e217
+-3e-3
 -1000000
 -6.8
 ```