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Add support for string literal property names in object maps.

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This commit is contained in:
Stephen Chung
2020-03-30 12:14:59 +08:00
parent 45ee51874f
commit fce51758d1
4 changed files with 52 additions and 26 deletions
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README.md
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@@ -729,6 +729,8 @@ let a = { 40 + 2 }; // 'a' is set to the value of the statement block, which
Variables
---------
[variables]: #variables
Variables in Rhai follow normal C naming rules (i.e. must contain only ASCII letters, digits and underscores '`_`').
Variable names must start with an ASCII letter or an underscore '`_`', must contain at least one ASCII letter, and must start with an ASCII letter before a digit.
@@ -761,7 +763,7 @@ x == 42; // the parent block's 'x' is not changed
Constants
---------
Constants can be defined using the `const` keyword and are immutable. Constants follow the same naming rules as [variables](#variables).
Constants can be defined using the `const` keyword and are immutable. Constants follow the same naming rules as [variables].
```rust
const x = 42;
@@ -1046,7 +1048,14 @@ Object maps
Object maps are dictionaries. Properties of any type (`Dynamic`) can be freely added and retrieved.
Object map literals are built within braces '`${`' ... '`}`' (_name_ `:` _value_ syntax similar to Rust)
and separated by commas '`,`'.
and separated by commas '`,`'. The property _name_ can be a simple variable name following the same
naming rules as [variables], or an arbitrary string literal.
Property values can be accessed via the dot notation (_object_ `.` _property_) or index notation (_object_ `[` _property_ `]`).
The dot notation allows only property names that follow the same naming rules as [variables].
The index notation allows setting/getting properties of arbitrary names (even the empty string).
**Important:** Trying to read a non-existent property returns `()` instead of causing an error.
The Rust type of a Rhai object map is `rhai::Map`.
@@ -1068,13 +1077,19 @@ Examples:
let y = ${ // object map literal with 3 properties
a: 1,
bar: "hello",
baz: 123.456
"baz!$@": 123.456, // like JS, you can use any string as property names...
"": false, // even the empty string!
a: 42 // <- syntax error: duplicated property name
};
y.a = 42;
y.a = 42; // access via dot notation
y.baz!$@ = 42; // <- syntax error: only proper variable names allowed in dot notation
y."baz!$@" = 42; // <- syntax error: strings not allowed in dot notation
print(y.a); // prints 42
print(y["bar"]); // prints "hello" - access via string index
print(y["baz!$@"]); // prints 123.456 - access via index notation
ts.obj = y; // object maps can be assigned completely (by value copy)
let foo = ts.list.a;
@@ -1096,6 +1111,9 @@ foo == 42;
y.has("a") == true;
y.has("xyz") == false;
y.xyz == (); // A non-existing property returns '()'
y["xyz"] == ();
print(y.len()); // prints 3
y.clear(); // empty the object map