From c0d8439f3a5391b2980a0302401e00365a47e5e4 Mon Sep 17 00:00:00 2001
From: Fabian Homborg <FHomborg@gmail.com>
Date: Fri, 1 Nov 2019 08:40:56 +0100
Subject: [PATCH] math: Print special error for logical operators

Until now, something like

`math '7 = 2'`

would complain about a "missing" operator.

Now we print an error about logical operators not being supported and
point the user towards `test`.

Fixes #6096
---
 src/builtin_math.cpp   | 2 ++
 src/tinyexpr.cpp       | 9 +++++++++
 src/tinyexpr.h         | 3 ++-
 tests/checks/math.fish | 5 +++++
 4 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/builtin_math.cpp b/src/builtin_math.cpp
index 822040930..611c29141 100644
--- a/src/builtin_math.cpp
+++ b/src/builtin_math.cpp
@@ -149,6 +149,8 @@ static const wchar_t *math_describe_error(te_error_t &error) {
             return _(L"Missing operator");
         case TE_ERROR_UNEXPECTED_TOKEN:
             return _(L"Unexpected token");
+        case TE_ERROR_LOGICAL_OPERATOR:
+            return _(L"Logical operations are not supported, use `test` instead");
         case TE_ERROR_UNKNOWN:
             return _(L"Expression is bogus");
         default:
diff --git a/src/tinyexpr.cpp b/src/tinyexpr.cpp
index 61c007e17..e16b87b6f 100644
--- a/src/tinyexpr.cpp
+++ b/src/tinyexpr.cpp
@@ -306,6 +306,15 @@ void next_token(state *s) {
                     case '\n':
                     case '\r':
                         break;
+                    case '=':
+                    case '>':
+                    case '<':
+                    case '&':
+                    case '|':
+                    case '!':
+                        s->type = TOK_ERROR;
+                        s->error = TE_ERROR_LOGICAL_OPERATOR;
+                        break;
                     default:
                         s->type = TOK_ERROR;
                         s->error = TE_ERROR_MISSING_OPERATOR;
diff --git a/src/tinyexpr.h b/src/tinyexpr.h
index fb945525b..bd6e93409 100644
--- a/src/tinyexpr.h
+++ b/src/tinyexpr.h
@@ -36,7 +36,8 @@ typedef enum {
     TE_ERROR_TOO_MANY_ARGS = 5,
     TE_ERROR_MISSING_OPERATOR = 6,
     TE_ERROR_UNEXPECTED_TOKEN = 7,
-    TE_ERROR_UNKNOWN = 8
+    TE_ERROR_LOGICAL_OPERATOR = 8,
+    TE_ERROR_UNKNOWN = 9
 } te_error_type_t;
 
 typedef struct te_error_t {
diff --git a/tests/checks/math.fish b/tests/checks/math.fish
index a66e9937a..a4fa92f69 100644
--- a/tests/checks/math.fish
+++ b/tests/checks/math.fish
@@ -126,3 +126,8 @@ math 0x 3
 # CHECK: 20
 # CHECK: 8
 # CHECK: 0
+
+math "42 >= 1337"
+# CHECKERR: math: Error: Logical operations are not supported, use `test` instead
+# CHECKERR: '42 >= 1337'
+# CHECKERR:     ^