fix erlang code generation with 0 literal denominator

Author: giacomocavalieri

CHANGELOG.md

@@ -20,6 +20,10 @@
 
   ([Adi Salimgereyev](https://github.com/abs0luty))
 
+- Improved the code generated on the Erlang target when dividing a `Float`
+  number by the literal number `0.0`.
+  ([Giacomo Cavalieri](https://github.com/giacomocavalieri))
+
 ### Build tool
 
 - When adding a package that does not exist on Hex, the message is a bit

compiler-core/src/ast/typed.rs

@@ -1,5 +1,3 @@
-use std::sync::OnceLock;
-
 use type_::{FieldMap, TypedCallArg};
 
 use super::*;
@@ -607,7 +605,7 @@ impl TypedExpr {
     pub fn is_non_zero_compile_time_number(&self) -> bool {
         match self {
             Self::Int { int_value, .. } => int_value != &BigInt::ZERO,
-            Self::Float { value, .. } => is_non_zero_number(value),
+            Self::Float { float_value, .. } => !float_value.value().is_zero(),
             Self::String { .. }
             | Self::Block { .. }
             | Self::Pipeline { .. }
@@ -636,7 +634,7 @@ impl TypedExpr {
     pub fn is_zero_compile_time_number(&self) -> bool {
         match self {
             Self::Int { int_value, .. } => int_value == &BigInt::ZERO,
-            Self::Float { value, .. } => !is_non_zero_number(value),
+            Self::Float { float_value, .. } => float_value.value().is_zero(),
             Self::String { .. }
             | Self::Block { .. }
             | Self::Pipeline { .. }
@@ -1655,15 +1653,6 @@ pub(crate) fn pairwise_all<A>(one: &[A], other: &[A], function: impl Fn((&A, &A)
     one.len() == other.len() && one.iter().zip(other).all(function)
 }
 
-fn is_non_zero_number(value: &EcoString) -> bool {
-    use regex::Regex;
-    static NON_ZERO: OnceLock<Regex> = OnceLock::new();
-
-    NON_ZERO
-        .get_or_init(|| Regex::new(r"[1-9]").expect("NON_ZERO regex"))
-        .is_match(value)
-}
-
 impl<'a> From<&'a TypedExpr> for Located<'a> {
     fn from(expression: &'a TypedExpr) -> Self {
         Located::Expression {

compiler-core/src/erlang.rs

@@ -1115,6 +1115,8 @@ fn statement_sequence<'a>(statements: &'a [TypedStatement], env: &mut Env<'a>) -
 fn float_div<'a>(left: &'a TypedExpr, right: &'a TypedExpr, env: &mut Env<'a>) -> Document<'a> {
     if right.is_non_zero_compile_time_number() {
         return binop_exprs(left, "/", right, env);
+    } else if right.is_zero_compile_time_number() {
+        return "+0.0".to_doc();
     }
 
     let left = expr(left, env);

compiler-core/src/erlang/snapshots/gleam_core__erlang__tests__float_division_by_literal_non_zero.snap

@@ -0,0 +1,20 @@
+---
+source: compiler-core/src/erlang/tests.rs
+expression: "\npub fn main() {\n  1.0 /. 2.0\n}        "
+---
+----- SOURCE CODE
+
+pub fn main() {
+  1.0 /. 2.0
+}        
+
+----- COMPILED ERLANG
+-module(my@mod).
+-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
+-define(FILEPATH, "project/test/my/mod.gleam").
+-export([main/0]).
+
+-file("project/test/my/mod.gleam", 2).
+-spec main() -> float().
+main() ->
+    1.0 / 2.0.

compiler-core/src/erlang/snapshots/gleam_core__erlang__tests__float_division_by_literal_zero.snap

@@ -0,0 +1,20 @@
+---
+source: compiler-core/src/erlang/tests.rs
+expression: "\npub fn main() {\n  1.0 /. 0.0\n}        "
+---
+----- SOURCE CODE
+
+pub fn main() {
+  1.0 /. 0.0
+}        
+
+----- COMPILED ERLANG
+-module(my@mod).
+-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
+-define(FILEPATH, "project/test/my/mod.gleam").
+-export([main/0]).
+
+-file("project/test/my/mod.gleam", 2).
+-spec main() -> float().
+main() ->
+    +0.0.

compiler-core/src/erlang/tests.rs

@@ -1013,3 +1013,23 @@ pub fn main() {
 }        "
     );
 }
+
+#[test]
+fn float_division_by_literal_zero() {
+    assert_erl!(
+        "
+pub fn main() {
+  1.0 /. 0.0
+}        "
+    );
+}
+
+#[test]
+fn float_division_by_literal_non_zero() {
+    assert_erl!(
+        "
+pub fn main() {
+  1.0 /. 2.0
+}        "
+    );
+}