From 8f9730d89e66ab1cbf08cbc0dea2a429d135e0da Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?William=20Herg=C3=A8s?= <william@herges.fr>
Date: Sun, 9 Nov 2025 12:49:15 +0100
Subject: feat(parser): supports implicit mult

---
 example/input.txt                |  4 ++--
 lib/main.ex                      |  7 ++++---
 src/elixir_math_parser.yrl       | 31 ++++++++++++++++---------------
 src/elixir_math_parser_lexer.xrl |  7 ++++---
 4 files changed, 26 insertions(+), 23 deletions(-)

diff --git a/example/input.txt b/example/input.txt
index 0d42cb7..a32d267 100644
--- a/example/input.txt
+++ b/example/input.txt
@@ -3,5 +3,5 @@ a = 7;; b = 4
 
 x = 20
 y = 3
-z = 6
-10 + z / y * x / 4
+z = 2y 
+10 + 4(z / y)(x / 4)
diff --git a/lib/main.ex b/lib/main.ex
index 5418da5..99c25ca 100644
--- a/lib/main.ex
+++ b/lib/main.ex
@@ -1,7 +1,8 @@
 defmodule ElixirMathParser.Main do
   def process_parse({:error, result}) do
-    IO.puts("\nParse error")
-    IO.inspect(result)
+    {line, _file, errors} = result
+    err = Enum.join(errors)
+    err <> " (line " <> to_string(line) <> ")"
   end
 
   def process_parse({:ok, tree}) do
@@ -26,7 +27,7 @@ defmodule ElixirMathParser.Main do
     res = process_parse(:elixir_math_parser.parse(tokens))
 
     if res != :ok do
-      IO.puts(res)
+      IO.puts(:stderr, "\n" <> res)
     end
   end
 end
diff --git a/src/elixir_math_parser.yrl b/src/elixir_math_parser.yrl
index 46340ae..86b36c8 100644
--- a/src/elixir_math_parser.yrl
+++ b/src/elixir_math_parser.yrl
@@ -3,19 +3,16 @@ Nonterminals
   statement
   statements
   expr
+  exprs
 .
 
 Terminals
   int
   var
-  '+'
-  '-'
-  '*'
-  '/'
+  break
+  '+' '-' '*' '/'
   '='
-  '('
-  ')'
-  ';;'
+  '(' ')'
 .
 
 Rootsymbol
@@ -33,18 +30,22 @@ root -> statements : '$1'.
 
 statements -> statement : ['$1'].
 statements -> statement statements : ['$1'|'$2'].
-statements -> statement ';;' statements : ['$1'|'$3'].
+statements -> statement break statements : ['$1'|'$3'].
+statements -> break : [].
 
-statement -> var '=' expr : {assign, '$1', '$3'}.
-statement -> expr : {eval, '$1'}.
+statement -> var '=' exprs : {assign, '$1', '$3'}.
+statement -> exprs : {eval, '$1'}.
+
+exprs -> expr       : '$1'.
+exprs -> expr exprs : {mul_op, '$1', '$2'}.
 
 expr -> int : unwrap('$1').
 expr -> var : '$1'.
-expr -> expr '+' expr : {add_op, '$1', '$3'}.
-expr -> expr '-' expr : {sub_op, '$1', '$3'}.
-expr -> expr '*' expr : {mul_op, '$1', '$3'}.
-expr -> expr '/' expr : {div_op, '$1', '$3'}.
-expr -> '(' expr ')'  : '$2'.
+expr -> exprs '+' exprs : {add_op, '$1', '$3'}.
+expr -> exprs '-' exprs : {sub_op, '$1', '$3'}.
+expr -> exprs '*' exprs : {mul_op, '$1', '$3'}.
+expr -> exprs '/' exprs : {div_op, '$1', '$3'}.
+expr -> '(' exprs ')' : '$2'.
 
 Erlang code.
 
diff --git a/src/elixir_math_parser_lexer.xrl b/src/elixir_math_parser_lexer.xrl
index a72f7e3..facf323 100644
--- a/src/elixir_math_parser_lexer.xrl
+++ b/src/elixir_math_parser_lexer.xrl
@@ -1,8 +1,9 @@
 Definitions.
 INT        = [0-9]+
 NAME       = [a-zA-Z_][a-zA-Z0-9_]*
-WHITESPACE = [\s\t\n\r]
-COMMENT    = #[^\n]*
+WHITESPACE = [\s\t\r]
+COMMENT    = #[^\n]*\n?
+BREAK      = [\n;;]
 
 Rules.
 \+            : {token, {'+',  TokenLine}}.
@@ -12,7 +13,7 @@ Rules.
 \=            : {token, {'=',  TokenLine}}.
 \(            : {token, {'(',  TokenLine}}.
 \)            : {token, {')',  TokenLine}}.
-;;            : {token, {';;',  TokenLine}}.
+{BREAK}+      : {token, {break,  TokenLine}}.
 {NAME}        : {token, {var, TokenLine, TokenChars}}.
 {INT}         : {token, {int,  TokenLine, TokenChars}}.
 {WHITESPACE}+ : skip_token.
-- 
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