Document operator precedence

fixes #7816

diff --git a/doc/15-language-reference.md b/doc/15-language-reference.md
index 17fab5fd8ace2554784c8e908fb17b09aaae2133..4fe62affd7d9bbfefa9e526661e536f1601b7d54 100644 (file)
--- a/doc/15-language-reference.md
+++ b/doc/15-language-reference.md
@@ -147,36 +147,40 @@ strings and numbers.
 
 ### <a id="expression-operators"></a> Operators
 
-The following operators are supported in expressions:
-
-Operator | Examples (Result)                             | Description
----------|-----------------------------------------------|--------------------------------
-!        | !"Hello" (false), !false (true)               | Logical negation of the operand
-~        | ~true (false)                                 | Bitwise negation of the operand
-+        | 1 + 3 (4), "hello " + "world" ("hello world") | Adds two numbers; concatenates strings
-+        | +3                                            | Unary plus
--        | 3 - 1 (2)                                     | Subtracts two numbers
--        | -3                                            | Unary minus
-*        | 5m * 10 (3000)                                | Multiplies two numbers
-/        | 5m / 5 (60)                                   | Divides two numbers
-%        | 17 % 12 (5)                                   | Remainder after division
-^        | 17 ^ 12 (29)                                  | Bitwise XOR
-&        | 7 & 3 (3)                                     | Binary AND
-&#124;   | 2 &#124; 3 (3)                                | Binary OR
-&&       | true && false (false), 3 && 7 (7), 0 && 7 (0) | Logical AND
-&#124;&#124; | true &#124;&#124; false (true), 0 || 7 (7)| Logical OR
-<        | 3 < 5 (true)                                  | Less than
->        | 3 > 5 (false)                                 | Greater than
-<=       | 3 <= 3 (true)                                 | Less than or equal
->=       | 3 >= 3 (true)                                 | Greater than or equal
-<<       | 4 << 8 (1024)                                 | Left shift
->>       | 1024 >> 4 (64)                                | Right shift
-==       | "hello" == "hello" (true), 3 == 5 (false)     | Equal to
-!=       | "hello" != "world" (true), 3 != 3 (false)     | Not equal to
-in       | "foo" in [ "foo", "bar" ] (true)              | Element contained in array
-!in      | "foo" !in [ "bar", "baz" ] (true)             | Element not contained in array
-()       | (3 + 3) * 5                                   | Groups sub-expressions
-()       | Math.random()                                 | Calls a function
+The following operators are supported in expressions. The operators are by descending precedence.
+
+Operator | Precedence | Examples (Result)                             | Description
+---------|------------|-----------------------------------------------|--------------------------------
+()       | 1          | (3 + 3) * 5                                   | Groups sub-expressions
+()       | 1          | Math.random()                                 | Calls a function
+[]       | 1          | a[3]                                          | Array subscript
+.        | 1          | a.b                                           | Element access
+!        | 2          | !"Hello" (false), !false (true)               | Logical negation of the operand
+~        | 2          | ~true (false)                                 | Bitwise negation of the operand
++        | 2          | +3                                            | Unary plus
+-        | 2          | -3                                            | Unary minus
+*        | 3          | 5m * 10 (3000)                                | Multiplies two numbers
+/        | 3          | 5m / 5 (60)                                   | Divides two numbers
+%        | 3          | 17 % 12 (5)                                   | Remainder after division
++        | 4          | 1 + 3 (4), "hello " + "world" ("hello world") | Adds two numbers; concatenates strings
+-        | 4          | 3 - 1 (2)                                     | Subtracts two numbers
+<<       | 5          | 4 << 8 (1024)                                 | Left shift
+>>       | 5          | 1024 >> 4 (64)                                | Right shift
+<        | 6         | 3 < 5 (true)                                  | Less than
+>        | 6         | 3 > 5 (false)                                 | Greater than
+<=       | 6         | 3 <= 3 (true)                                 | Less than or equal
+>=       | 6         | 3 >= 3 (true)                                 | Greater than or equal
+in       | 7          | "foo" in [ "foo", "bar" ] (true)              | Element contained in array
+!in      | 7          | "foo" !in [ "bar", "baz" ] (true)             | Element not contained in array
+==       | 8         | "hello" == "hello" (true), 3 == 5 (false)     | Equal to
+!=       | 8         | "hello" != "world" (true), 3 != 3 (false)     | Not equal to
+&        | 9          | 7 & 3 (3)                                     | Binary AND
+^        | 10          | 17 ^ 12 (29)                                  | Bitwise XOR
+&#124;   | 11          | 2 &#124; 3 (3)                                | Binary OR
+&&       | 13         | true && false (false), 3 && 7 (7), 0 && 7 (0) | Logical AND
+&#124;&#124; | 14     | true &#124;&#124; false (true), 0 || 7 (7)| Logical OR
+=        | 12         | a = 3                                         | Assignment
+=>       | 15         | x => x * x (function with arg x)              | Lambda, for loop
 
 ### <a id="function-calls"></a> Function Calls
 

diff --git a/lib/config/config_parser.yy b/lib/config/config_parser.yy
index 83a2e55149094c87f8293729f944c659409c3c60..357bf40fcefe3e29eb65f74ca97b8a43fc605b6d 100644 (file)
--- a/lib/config/config_parser.yy
+++ b/lib/config/config_parser.yy
@@ -210,20 +210,20 @@ static void MakeRBinaryOp(Expression** result, Expression *left, Expression *rig
 %right T_FOLLOWS
 %right T_INCLUDE T_INCLUDE_RECURSIVE T_OBJECT T_TEMPLATE T_APPLY T_IMPORT T_ASSIGN T_IGNORE T_WHERE
 %right T_FUNCTION T_FOR
+%left T_SET T_SET_ADD T_SET_SUBTRACT T_SET_MULTIPLY T_SET_DIVIDE T_SET_MODULO T_SET_XOR T_SET_BINARY_AND T_SET_BINARY_OR
 %left T_LOGICAL_OR
 %left T_LOGICAL_AND
 %left T_RETURN
 %left T_IDENTIFIER
-%left T_SET T_SET_ADD T_SET_SUBTRACT T_SET_MULTIPLY T_SET_DIVIDE T_SET_MODULO T_SET_XOR T_SET_BINARY_AND T_SET_BINARY_OR
-%nonassoc T_EQUAL T_NOT_EQUAL
-%nonassoc T_LESS_THAN T_LESS_THAN_OR_EQUAL T_GREATER_THAN T_GREATER_THAN_OR_EQUAL
 %left T_BINARY_OR
-%left T_XOR T_MODULO
+%left T_XOR
 %left T_BINARY_AND
+%nonassoc T_EQUAL T_NOT_EQUAL
 %left T_IN T_NOT_IN
+%nonassoc T_LESS_THAN T_LESS_THAN_OR_EQUAL T_GREATER_THAN T_GREATER_THAN_OR_EQUAL
 %left T_SHIFT_LEFT T_SHIFT_RIGHT
 %left T_PLUS T_MINUS
-%left T_MULTIPLY T_DIVIDE_OP
+%left T_MULTIPLY T_DIVIDE_OP T_MODULO
 %left UNARY_MINUS UNARY_PLUS
 %right '!' '~'
 %left '.' '(' '['

diff --git a/test/config-ops.cpp b/test/config-ops.cpp
index b812c34bd8569eddb22f9a9ca608892805cc2cd8..f9686d62c89cea2ffe95c9ceedb1d86defc67f05 100644 (file)
--- a/test/config-ops.cpp
+++ b/test/config-ops.cpp
@@ -268,15 +268,15 @@ BOOST_AUTO_TEST_CASE(advanced)
        BOOST_CHECK(expr->Evaluate(frame));
        delete expr;
 
-       expr = ConfigCompiler::CompileText("<test>", "7 | 8 == 15");
+       expr = ConfigCompiler::CompileText("<test>", "(7 | 8) == 15");
        BOOST_CHECK(expr->Evaluate(frame));
        delete expr;
 
-       expr = ConfigCompiler::CompileText("<test>", "7 ^ 8 == 15");
+       expr = ConfigCompiler::CompileText("<test>", "(7 ^ 8) == 15");
        BOOST_CHECK(expr->Evaluate(frame));
        delete expr;
 
-       expr = ConfigCompiler::CompileText("<test>", "7 & 15 == 7");
+       expr = ConfigCompiler::CompileText("<test>", "(7 & 15) == 7");
        BOOST_CHECK(expr->Evaluate(frame));
        delete expr;
 
@@ -288,15 +288,15 @@ BOOST_AUTO_TEST_CASE(advanced)
        BOOST_CHECK(expr->Evaluate(frame));
        delete expr;
 
-       expr = ConfigCompiler::CompileText("<test>", "7 | 8 > 14");
+       expr = ConfigCompiler::CompileText("<test>", "(7 | 8) > 14");
        BOOST_CHECK(expr->Evaluate(frame));
        delete expr;
 
-       expr = ConfigCompiler::CompileText("<test>", "7 ^ 8 > 14");
+       expr = ConfigCompiler::CompileText("<test>", "(7 ^ 8) > 14");
        BOOST_CHECK(expr->Evaluate(frame));
        delete expr;
 
-       expr = ConfigCompiler::CompileText("<test>", "7 & 15 > 6");
+       expr = ConfigCompiler::CompileText("<test>", "(7 & 15) > 6");
        BOOST_CHECK(expr->Evaluate(frame));
        delete expr;