Struct endbasic_core::syms::Symbols

pub struct Symbols { /* fields omitted */ }

Storage for all symbols that exist at runtime.

Implementations

impl Symbols

pub fn add_command(&mut self, command: Rc<dyn Command>)

Registers the given builtin command.

Given that commands cannot be defined at runtime, specifying a non-unique name results in a panic.

pub fn add_function(&mut self, function: Rc<dyn Function>)

Registers the given builtin function.

Given that functions cannot be defined at runtime, specifying a non-unique name results in a panic.

pub fn as_hashmap(&self) -> &HashMap<String, Symbol>

Returns the mapping of all symbols.

pub fn clear(&mut self)

Clears all user-defined symbols.

pub fn dim(&mut self, name: &str, vartype: VarType) -> Result<()>

Defines a new variable name of type vartype. The variable must not yet exist.

pub fn dim_array(
    &mut self,
    name: &str,
    subtype: VarType,
    dimensions: Vec<usize>
) -> Result<()>

Defines a new array name of type subtype with dimensions. The array must not yet exist, and the name may not overlap function or variable names.

pub fn get(&self, vref: &VarRef) -> Result<Option<&Symbol>>

Obtains the value of a symbol or None if it is not defined.

Returns an error if the type annotation in the symbol reference does not match its type.

pub fn get_mut(&mut self, vref: &VarRef) -> Result<Option<&mut Symbol>>

Obtains the value of a symbol or None if it is not defined.

Returns an error if the type annotation in the symbol reference does not match its type.

pub fn get_var(&self, vref: &VarRef) -> Result<&Value>

Obtains the value of a variable.

Returns an error if the variable is not defined, if the referenced symbol is not a variable, or if the type annotation in the variable reference does not match the type of the value that the variable contains.

pub fn qualify_varref(&self, vref: &VarRef) -> Result<VarRef>

Adds a type annotation to the symbol reference if the symbol is already defined and the reference lacks one.

pub fn set_var(&mut self, vref: &VarRef, value: Value) -> Result<()>

Sets the value of a variable.

If vref contains a type annotation, the type of the value must be compatible with that type annotation.

If the variable is already defined, then the type of the new value must be compatible with the existing variable. In other words: a variable cannot change types while it’s alive.

Trait Implementations

impl Default for Symbols

fn default() -> Symbols

Returns the “default value” for a type.