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Statements
----------
.. crowbar:element:: Block <- '{' Statement* '}'
Compile-time Behavior:
A block is a possibly-empty sequence of statements surrounded by curly braces.
Any declaration or definition within the block must not be visible outside of the block.
Runtime Behavior:
When a block is executed, each of the containing statements, in linear order, is executed.
.. crowbar:element:: Statement <- VariableDefinition / StructureStatement / FlowControlStatement / AssignmentStatement / FragileStatement / ExpressionStatement / EmptyStatement
Crowbar has many different types of statement.
.. crowbar:element:: EmptyStatement <- ';'
Compile-time Behavior:
None.
Runtime Behavior:
None.
.. crowbar:element:: FragileStatement <- 'fragile' Statement
Some behaviors are difficult to ensure the robustness of at compile time, and these behaviors are defined in this specification as *fragile*.
Fragile behaviors used outside of fragile statements should produce a compiler error.
Compile-time Behavior:
Fragile behaviors used inside a fragile statement must not produce a compiler error for their fragility.
Nesting fragile statements should produce a compiler error.
Runtime Behavior:
The contained statement is executed.
.. crowbar:element:: ExpressionStatement <- Expression ';'
Compile-time Behavior:
If the expression is not a function call, the compiler may emit a warning.
Runtime Behavior:
The expression is evaluated and the resulting value is discarded.
Function calls must be fully evaluated, but expressions that are not function calls may be optimized out.
.. toctree::
:maxdepth: 1
variables
structure
flow-control
assignment
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