feat: add == and != operators for bool, number, and string types with type-checking

Implement equality and inequality operators across three primitive types in the compiler and runtime. Add `bool_eqeq`/`bool_bangeq`, `num_eqeq`/`num_bangeq`, and `string_eqeq`/`string_bangeq` primitives that return false/true respectively when comparing against incompatible types. Update the parse rule table with `INFIX_OPERATOR` macros for `TOKEN_EQEQ` and `TOKEN_BANGEQ` at `PREC_COMPARISON` precedence. Include test files `bool_equality.wren`, `number_equality.wren`, and `string_equality.wren` covering cross-type comparisons and edge cases.

test/block_call.wren

@@ -1 +1,3 @@
 io.write({ 123 }.call) // expect: 123
+
+// TODO(bob): Arguments.

test/bool_equality.wren

@@ -0,0 +1,23 @@
+io.write(true == true)    // expect: true
+io.write(true == false)   // expect: false
+io.write(false == true)   // expect: false
+io.write(false == false)  // expect: true
+
+// Not equal to other types.
+io.write(true == 1)        // expect: false
+io.write(false == 0)       // expect: false
+io.write(true == "true")   // expect: false
+io.write(false == "false") // expect: false
+io.write(false == "")      // expect: false
+
+io.write(true != true)    // expect: false
+io.write(true != false)   // expect: true
+io.write(false != true)   // expect: true
+io.write(false != false)  // expect: false
+
+// Not equal to other types.
+io.write(true != 1)        // expect: true
+io.write(false != 0)       // expect: true
+io.write(true != "true")   // expect: true
+io.write(false != "false") // expect: true
+io.write(false != "")      // expect: true

test/grammar.wren

@@ -5,5 +5,25 @@ io.write(2 + 3 * 4) // expect: 14
 // * has higher precedence than -.
 io.write(20 - 3 * 4) // expect: 8
 
+// / has higher precedence than +.
+io.write(2 + 6 / 3) // expect: 4
+
+// / has higher precedence than -.
+io.write(2 - 6 / 3) // expect: 0
+
+// < has higher precedence than ==.
+io.write(false == 2 < 1) // expect: true
+
+// > has higher precedence than ==.
+io.write(false == 1 > 2) // expect: true
+
+// <= has higher precedence than ==.
+io.write(false == 2 <= 1) // expect: true
+
+// >= has higher precedence than ==.
+io.write(false == 1 >= 2) // expect: true
+
+// TODO(bob): %, associativity.
+
 // Using () for grouping.
 io.write((2 * (6 - (2 + 2)))) // expect: 4

test/number_equality.wren

@@ -0,0 +1,19 @@
+io.write(123 == 123)  // expect: true
+io.write(123 == 124)  // expect: false
+io.write(-3 == 3)     // expect: false
+
+// Not equal to other types.
+io.write(123 == "123") // expect: false
+io.write(1 == true)    // expect: false
+io.write(0 == false)   // expect: false
+
+io.write(123 != 123)  // expect: false
+io.write(123 != 124)  // expect: true
+io.write(-3 != 3)     // expect: true
+
+// Not equal to other types.
+io.write(123 != "123") // expect: true
+io.write(1 != true)    // expect: true
+io.write(0 != false)   // expect: true
+
+// TODO(bob): Should 0 == -0?

test/string_equality.wren

@@ -0,0 +1,19 @@
+io.write("" == "")          // expect: true
+io.write("abcd" == "abcd")  // expect: true
+io.write("abcd" == "d")     // expect: false
+io.write("e" == "abcd")     // expect: false
+io.write("" == "abcd")      // expect: false
+
+// Not equal to other types.
+io.write("1" == 1)        // expect: false
+io.write("true" == true)  // expect: false
+
+io.write("" != "")          // expect: false
+io.write("abcd" != "abcd")  // expect: false
+io.write("abcd" != "d")     // expect: true
+io.write("e" != "abcd")     // expect: true
+io.write("" != "abcd")      // expect: true
+
+// Not equal to other types.
+io.write("1" != 1)        // expect: true
+io.write("true" != true)  // expect: true