Dialect differences

The list below summarizes features of the Go implementation that are known to differ from the Java implementation of Starlark used by Bazel. Some of these features may be controlled by global options to allow applications to mimic the Bazel dialect more closely. Our goal is eventually to eliminate all such differences on a case-by-case basis. See Starlark spec issue 20.

• Integers are represented with infinite precision.
• Integer arithmetic is exact.
• Floating-point literals are supported (option: -float).
• The float built-in function is provided (option: -float).
• Real division using float / float is supported (option: -float).
• String interpolation supports the [ioxXeEfFgGc] conversions.
• def statements may be nested (option: -nesteddef).
• lambda expressions are supported (option: -lambda).
• String elements are bytes.
• Non-ASCII strings are encoded using UTF-8.
• Strings support octal and hex byte escapes.
• Strings have the additional methods elem_ords, codepoint_ords, and codepoints.
• The chr and ord built-in functions are supported.
• The set built-in function is provided (option: -set).
• set & set and set | set compute set intersection and union, respectively.
• assert is a valid identifier.
• Dot expressions may appear on the left side of an assignment: x.f = 1.
• type(x) returns "builtin_function_or_method" for built-in functions.
• if, for, and while are permitted at top level (option: -globalreassign).
• top-level rebindings are permitted (option: -globalreassign).