Documentation ¶
Overview ¶
Package goal provides an API to goal's interpreter.
In order to evaluate code in the Goal programming language, first a new context has to be created.
ctx := goal.NewContext()
This context can then be used to Compile some code, and then Run it. It is possible to customize the context by registering new unary and binary operators or keywords using the RegisterMonad and RegisterDyad methods.
See tests in context_test.go, the os package, as well as programs under cmd/* for usage examples.
Index ¶
- type A
- type AB
- func (x *AB) Append(ctx *Context, dst []byte, compact bool) []byte
- func (x *AB) At(i int) V
- func (x *AB) IsBoolean() bool
- func (x *AB) Len() int
- func (x *AB) Less(i, j int) bool
- func (x *AB) LessT(y BV) bool
- func (x *AB) MarkImmutable()
- func (x *AB) MarshalJSON() ([]byte, error)
- func (x *AB) Matches(y BV) bool
- func (x *AB) Reusable() bool
- func (x *AB) Swap(i, j int)
- func (x *AB) Type() string
- type AF
- func (x *AF) Append(ctx *Context, dst []byte, compact bool) []byte
- func (x *AF) At(i int) V
- func (x *AF) Len() int
- func (x *AF) Less(i, j int) bool
- func (x *AF) LessT(y BV) bool
- func (x *AF) MarkImmutable()
- func (x *AF) MarshalJSON() ([]byte, error)
- func (x *AF) Matches(y BV) bool
- func (x *AF) Reusable() bool
- func (x *AF) Swap(i, j int)
- func (x *AF) Type() string
- type AI
- func (x *AI) Append(ctx *Context, dst []byte, compact bool) []byte
- func (x *AI) At(i int) V
- func (x *AI) Len() int
- func (x *AI) Less(i, j int) bool
- func (x *AI) LessT(y BV) bool
- func (x *AI) MarkImmutable()
- func (x *AI) MarshalJSON() ([]byte, error)
- func (x *AI) Matches(y BV) bool
- func (x *AI) Reusable() bool
- func (x *AI) Swap(i, j int)
- func (x *AI) Type() string
- type AS
- func (x *AS) Append(ctx *Context, dst []byte, compact bool) []byte
- func (x *AS) At(i int) V
- func (x *AS) Len() int
- func (x *AS) Less(i, j int) bool
- func (x *AS) LessT(y BV) bool
- func (x *AS) MarkImmutable()
- func (x *AS) MarshalJSON() ([]byte, error)
- func (x *AS) Matches(y BV) bool
- func (x *AS) Reusable() bool
- func (x *AS) Swap(i, j int)
- func (x *AS) Type() string
- type AV
- func (x *AV) Append(ctx *Context, dst []byte, compact bool) []byte
- func (x *AV) At(i int) V
- func (x *AV) Len() int
- func (x *AV) Less(i, j int) bool
- func (x *AV) LessT(y BV) bool
- func (x *AV) MarkImmutable()
- func (x *AV) MarshalJSON() ([]byte, error)
- func (x *AV) Matches(y BV) bool
- func (x *AV) Reusable() bool
- func (x *AV) Swap(i, j int)
- func (x *AV) Type() string
- type Array
- type BV
- type Callable
- type Context
- func (ctx *Context) AssignGlobal(name string, x V)
- func (ctx *Context) AssignedLast() bool
- func (ctx *Context) Compile(s, loc, pfx string) error
- func (ctx *Context) Eval(s string) (V, error)
- func (ctx *Context) EvalPackage(s, loc, pfx string) (V, error)
- func (ctx *Context) Get(key string) any
- func (ctx *Context) GetGlobal(name string) (V, bool)
- func (ctx *Context) GetVariadic(name string) (V, VariadicFunc)
- func (ctx *Context) GlobalNames(names []string) []string
- func (ctx *Context) Keywords(names []string) []string
- func (ctx *Context) RegisterDyad(name string, vf VariadicFunc) V
- func (ctx *Context) RegisterMonad(name string, vf VariadicFunc) V
- func (ctx *Context) Run() (V, error)
- func (ctx *Context) Set(key string, value any)
- func (ctx *Context) String() string
- type D
- func (d *D) Append(ctx *Context, dst []byte, compact bool) []byte
- func (d *D) Get(x V) (V, bool)
- func (d *D) KeyArray() Array
- func (d *D) Keys() V
- func (d *D) Len() int
- func (d *D) LessT(y BV) bool
- func (d *D) MarkImmutable()
- func (d *D) MarshalJSON() ([]byte, error)
- func (d *D) Matches(y BV) bool
- func (d *D) Type() string
- func (d *D) ValueArray() Array
- func (d *D) Values() V
- type ErrPackageImported
- type Error
- type Panic
- func (e *Panic) Append(ctx *Context, dst []byte, compact bool) []byte
- func (e *Panic) Error() string
- func (e *Panic) ErrorStack() string
- func (e *Panic) LessT(y BV) bool
- func (e *Panic) Matches(y BV) bool
- func (e *Panic) Type() string
- func (e *Panic) Unwrap() error
- func (e *Panic) WithPrefix(pfx string) *Panic
- type R
- type S
- type V
- func Apply2FloatFunc(x, y V, f func(float64, float64) float64) V
- func ApplyFloatFunc(x V, f func(float64) float64) V
- func Errorf(format string, a ...any) V
- func NewAB(x []byte) V
- func NewAF(x []float64) V
- func NewAI(x []int64) V
- func NewAS(x []string) V
- func NewAV(x []V) V
- func NewD(keys, values V) V
- func NewDict(keys, values Array) V
- func NewError(x V) V
- func NewF(f float64) V
- func NewGap() V
- func NewI(i int64) V
- func NewPanic(msg string) V
- func NewPanicError(err error) V
- func NewPanicV(x *Panic) V
- func NewProjection(x V, args []V) V
- func NewR(re *regexp.Regexp) V
- func NewS(s string) V
- func NewV(x BV) V
- func Panicf(format string, a ...any) V
- func (x V) Append(ctx *Context, dst []byte, compact bool) []byte
- func (x V) Apply(ctx *Context, args []V) V
- func (x V) Apply2(ctx *Context, y, z V) V
- func (x V) ApplyAt(ctx *Context, y V) V
- func (x V) BV() BV
- func (x V) Error() *Error
- func (x V) F() float64
- func (x V) I() int64
- func (x V) IsBV() bool
- func (x V) IsCallable() bool
- func (x V) IsError() bool
- func (x V) IsF() bool
- func (x V) IsFalse() bool
- func (x V) IsFunction() bool
- func (x V) IsGap() bool
- func (x V) IsI() bool
- func (x V) IsPanic() bool
- func (x V) IsProjection() bool
- func (x V) IsTrue() bool
- func (x V) Len() int
- func (x V) LessT(y V) bool
- func (x V) MarkImmutable()
- func (x V) MarshalJSON() ([]byte, error)
- func (x V) Matches(y V) bool
- func (x V) Panic() *Panic
- func (x V) Rank(ctx *Context) int
- func (x V) Sprint(ctx *Context, compact bool) string
- func (x V) Type() string
- type VariadicFunc
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type A ¶ added in v0.19.0
type A[T any] struct { // Slice is the underlying immutable slice of values. It should not be // modified unless Reusable returns true, and in such a case, you should mark // any new stored values with MarkImmutable (except for values that are // always immutable, like strings or unboxed values). Slice []T // contains filtered or unexported fields }
A is a generic type used to represent arrays. Only specific instantiations implement the BV and Array interfaces.
type AB ¶
AB represents an array of bytes. From Goal's perspective, it's the same as AI. It's used as an optimization to save space for small-integers, in particular for arrays of booleans (0s and 1s).
func (*AB) Append ¶ added in v0.6.0
Append appends a unique program representation of the value to dst, and returns the extended buffer.
func (*AB) IsBoolean ¶ added in v0.16.0
IsBoolean reports whether the array of bytes is known to contain only 1s and 0s.
func (*AB) MarkImmutable ¶ added in v0.19.0
func (x *AB) MarkImmutable()
MarkImmutable marks the value as definitively non-reusable. You can use this method to tell the optimizer that it cannot reuse its memory anymore. In particular, you should call this method before storing a value within a user-defined boxed value type.
func (*AB) MarshalJSON ¶ added in v0.25.0
MarshalJSON implements json.Marshaler.
func (*AB) Reusable ¶ added in v0.24.0
Reusable reports whether the array value and its underlying slice are reusable. Note that reusable values can be modified in-place by some operations, so use MarkImmutable if you want to avoid any such mutations. Always check Reusable before modifying an Array.
type AF ¶
AF represents an array of float64 values.
func (*AF) Append ¶ added in v0.6.0
Append appends a unique program representation of the value to dst, and returns the extended buffer.
func (*AF) MarkImmutable ¶ added in v0.19.0
func (x *AF) MarkImmutable()
MarkImmutable marks the value as definitively non-reusable. You can use this method to tell the optimizer that it cannot reuse its memory anymore. In particular, you should call this method before storing a value within a user-defined boxed value type.
func (*AF) MarshalJSON ¶ added in v0.25.0
MarshalJSON implements json.Marshaler.
func (*AF) Reusable ¶ added in v0.24.0
Reusable reports whether the array value and its underlying slice are reusable. Note that reusable values can be modified in-place by some operations, so use MarkImmutable if you want to avoid any such mutations. Always check Reusable before modifying an Array.
type AI ¶
AI represents an array of int64 values.
func (*AI) Append ¶ added in v0.6.0
Append appends a unique program representation of the value to dst, and returns the extended buffer.
func (*AI) MarkImmutable ¶ added in v0.19.0
func (x *AI) MarkImmutable()
MarkImmutable marks the value as definitively non-reusable. You can use this method to tell the optimizer that it cannot reuse its memory anymore. In particular, you should call this method before storing a value within a user-defined boxed value type.
func (*AI) MarshalJSON ¶ added in v0.25.0
MarshalJSON implements json.Marshaler.
func (*AI) Reusable ¶ added in v0.24.0
Reusable reports whether the array value and its underlying slice are reusable. Note that reusable values can be modified in-place by some operations, so use MarkImmutable if you want to avoid any such mutations. Always check Reusable before modifying an Array.
type AS ¶
AS represents an array of strings.
func (*AS) Append ¶ added in v0.6.0
Append appends a unique program representation of the value to dst, and returns the extended buffer.
func (*AS) MarkImmutable ¶ added in v0.19.0
func (x *AS) MarkImmutable()
MarkImmutable marks the value as definitively non-reusable. You can use this method to tell the optimizer that it cannot reuse its memory anymore. In particular, you should call this method before storing a value within a user-defined boxed value type.
func (*AS) MarshalJSON ¶ added in v0.25.0
MarshalJSON implements json.Marshaler.
func (*AS) Reusable ¶ added in v0.24.0
Reusable reports whether the array value and its underlying slice are reusable. Note that reusable values can be modified in-place by some operations, so use MarkImmutable if you want to avoid any such mutations. Always check Reusable before modifying an Array.
type AV ¶
AV represents a generic array. The elements of a generic array are marked as immutable, and they should not be representable together in a specialized array. In other words, it should be the canonical form of the array.
func (*AV) Append ¶ added in v0.6.0
Append appends a unique program representation of the value to dst, and returns the extended buffer.
func (*AV) MarkImmutable ¶ added in v0.19.0
func (x *AV) MarkImmutable()
MarkImmutable marks the value as definitively non-reusable. You can use this method to tell the optimizer that it cannot reuse its memory anymore. In particular, you should call this method before storing a value within a user-defined boxed value type.
func (*AV) MarshalJSON ¶ added in v0.25.0
MarshalJSON implements json.Marshaler.
func (*AV) Reusable ¶ added in v0.24.0
Reusable reports whether the array value and its underlying slice are reusable. Note that reusable values can be modified in-place by some operations, so use MarkImmutable if you want to avoid any such mutations. Always check Reusable before modifying an Array.
type Array ¶ added in v0.19.0
type Array interface { BV sort.Interface // At returns the value at index i, assuming it's not out of bounds. At(i int) V // Len returns the value's length. Len() int // Reusable reports whether the array value and its underlying slice are // reusable. Note that reusable values can be modified in-place by some // operations, so use MarkImmutable if you want to avoid any such mutations. // Always check Reusable before modifying an Array. Reusable() bool // contains filtered or unexported methods }
Array interface is satisfied by the different kinds of supported built-in array values. It can be used to handle arrays in a generic way when appropriate. Note that Array values also satisfy the BV interface.
func NewArray ¶ added in v0.24.0
NewArray returns a new array from a slice of generic values. The result value will be an array in canonical form. If the values are all of the same specialized type, like integers, floats, or strings, the underlying array will use a specialized representation, instead of a generic one.
It is the same as NewAV, but returns an Array value instead of a generic value.
type BV ¶ added in v0.19.0
type BV interface { // Append appends a unique program representation of the value to dst, // and returns the extended buffer. It should not store the returned // buffer elsewhere, so that it's possible to safely convert it to // string without allocations. The compact boolean determines whether // insignificant whitespace should be removed or not. If passed a nil // context, Append should produce a unique string suitable for hashing. Append(ctx *Context, dst []byte, compact bool) []byte // LessT reports whether the value should be orderer before the given // one. It is used for sorting values, but not for element-wise // comparison with < and >. It should produce a strict total order, // that is, irreflexive (~x<x), asymmetric (if x<y then ~y<x), // transitive, connected. LessT(BV) bool // Matches reports whether the two values match like in x~y. Matches(BV) bool // Type returns the name of the value's type. It may be used by LessT to // sort non-comparable values using lexicographic order. This means // Type should return different values for non-comparable values. Type() string }
BV is the interface satisfied by all boxed values. It can be satisfied by user-defined types.
type Callable ¶ added in v0.24.0
type Callable interface { BV // Apply calls the value with one or more arguments. The arguments are // provided in stack order, as in the right to left semantics used by // the language: the first argument is the last element. Apply(*Context, []V) V }
Callable represents user-defined boxed values that can be applied. To check if any kind of value (built-in or user-defined) is callable, use the IsCallable method for type V.
type Context ¶
type Context struct { // Log is the output writer for logging with \expr and rt.log (defaults // to io.Discard). Log io.Writer // contains filtered or unexported fields }
Context holds the state of the interpreter. Context values have to be created with NewContext.
func NewContext ¶
func NewContext() *Context
NewContext returns a new context for compiling and interpreting code, with default parameters.
func (*Context) AssignGlobal ¶
AssignGlobal assigns a value to a global variable name.
func (*Context) AssignedLast ¶
AssignedLast reports whether the last compiled expression was an assignment. The intended use for this method is avoiding echo in REPL in such a case.
func (*Context) Compile ¶
Compile parses and compiles code from the given source string in the current context. The loc argument is the location used for error reporting and represents usually a filename. The pfx is the default dot prefix for globals (an empty pfx disables dot prefix). For non-empty locations, Compile handles and skips shebang line (if any). Also, if the same non-empty location was already compiled with the same global prefix, an error ErrPackageImported is returned.
You cannot call it within a variadic function, as some information of the current execution state would be lost. Use EvalPackage instead in such case, which saves and restores information related to the current execution state.
func (*Context) Eval ¶
Eval calls Compile with the given string and an empty location and prefix, and then Run.
You cannot call it within a variadic function. Use EvalPackage instead in such case.
func (*Context) EvalPackage ¶
EvalPackage calls Compile with the string s as source, loc as error location (usually a filename), pfx as prefix for global variables (usually a filename without the extension), and then Run. If a package with same location and prefix has already been evaluated, it returns ErrPackageImported. This means that even though Goal allows, for convenience, to evaluate or import with the same location and prefix several times, only the first one counts.
The package's current execution state is saved and then restored, so unlike Compile, Run and Eval, the EvalPackage method is designed to be directly called within a variadic function.
func (*Context) Get ¶ added in v0.24.0
Get returns the value corresponding to the given key, as previously set with the Set method.
func (*Context) GetGlobal ¶
GetGlobal returns the value attached to a global variable with the given name.
func (*Context) GetVariadic ¶ added in v0.10.0
func (ctx *Context) GetVariadic(name string) (V, VariadicFunc)
GetVariadic returns the variadic value registered with a given keyword or symbol, along its associated variadic function. It returns a zero value and nil function if there is no registered variadic with such name.
func (*Context) GlobalNames ¶ added in v0.38.0
GlobalNames returns a string slice with the names of all global variables. The provided argument is used as a buffer for the result if it's large enough.
Note that the list of names does not include the names of globals that have not been assigned yet.
func (*Context) Keywords ¶ added in v0.38.0
Keywords returns a string slice of all keywords. The provided argument is used as a buffer for the result if it's large enough.
func (*Context) RegisterDyad ¶
func (ctx *Context) RegisterDyad(name string, vf VariadicFunc) V
RegisterDyad adds a variadic function to the context, and generates a new dyadic keyword or operator for that variadic (parsing will search for a left argument). The variadic is also returned as a value.
You cannot call it within a variadic function.
func (*Context) RegisterMonad ¶
func (ctx *Context) RegisterMonad(name string, vf VariadicFunc) V
RegisterMonad adds a variadic function to the context, and generates a new monadic keyword or operator for that variadic (parsing will not search for a left argument). The variadic is also returned as a value. Note that while a keyword defined in such a way will not take a left argument, it is still possible to pass several arguments to it with bracket indexing, like for any value. Also, this function cannot be used to change the dyadic nature of builtin symbols.
You cannot call it within a variadic function.
func (*Context) Run ¶
Run runs compiled code in the current context, if not already done, and returns the result value (if any).
Like Compile, you cannot call it within a variadic function.
type D ¶ added in v0.19.0
type D struct {
// contains filtered or unexported fields
}
D represents a dictionary.
func (*D) Append ¶ added in v0.19.0
Append appends a unique program representation of the value to dst, and returns the extended buffer.
func (*D) Get ¶ added in v0.39.0
Get is a convenience method that returns either the value associated to the first occurrence of the given key along a true boolean, or a zero value along a false boolean otherwise. This performs a simple generic linear search. If performance matters, you may prefer to use ApplyAt on the dict value, which works like indexing in Goal and allows to retrieve efficiently several values at once, but returns a zero value on outdexing and requires enlisting non-atom values if you want to search for them as a whole.
func (*D) KeyArray ¶ added in v0.24.0
KeyArray returns the keys of the dictionary as an Array value.
func (*D) Len ¶ added in v0.19.0
Len returns the length of the dictionary, that is the common length to its key and value arrays.
func (*D) MarkImmutable ¶ added in v0.19.0
func (d *D) MarkImmutable()
MarkImmutable marks the value as definitively non-reusable. You can use this method to tell the optimizer that it cannot reuse its memory anymore. In particular, you should call this method before storing a value within a user-defined boxed value type.
func (*D) MarshalJSON ¶ added in v0.25.0
MarshalJSON implements json.Marshaler. Note that not all generic values can be marshalled, only unboxed integers and floats, as well as boxed values implementing json.Marshaler. Also, nested lists are not supported for keys. The json builtin in Goal is more tolerant and stringifies others kinds of values before encoding.
func (*D) ValueArray ¶ added in v0.24.0
ValueArray returns the values of the dictionary as an Array value.
type ErrPackageImported ¶
type ErrPackageImported struct{}
ErrPackageImported is returned by EvalPackage and Compile for packages that have already been processed (same prefix and location).
func (ErrPackageImported) Error ¶
func (e ErrPackageImported) Error() string
type Error ¶ added in v0.41.0
type Error struct {
// contains filtered or unexported fields
}
Error represents a recoverable error. It may contain some goal value of any kind.
func (*Error) Append ¶ added in v0.41.0
Append appends a unique program representation of the value to dst, and returns the extended buffer.
Note that the program representation is not the same as the error message: use the Msg method for that.
type Panic ¶ added in v0.26.0
type Panic struct { Err error // error message (without location) // contains filtered or unexported fields }
Panic represents a fatal error returned by any Context method.
While Panic also satisfies the BV interface, you shouldn't create generic panic values from a Panic using NewV but NewPanicV instead. Panic is a special kind of boxed value that has to be marked specially so that checking for panics can efficiently be handled by the runtime.
Note that Panic values are not meant to be used explicitly from Goal code. In particular, they should not be assigned to variables or stored in generic arrays: use an Error value instead for such purposes.
func (*Panic) Append ¶ added in v0.26.0
Append appends a unique program representation of the value to dst, and returns the extended buffer.
func (*Panic) Error ¶ added in v0.26.0
Error returns the panic message without location information.
func (*Panic) ErrorStack ¶ added in v0.26.0
ErrorStack returns the full panic message with locations and source information obtained from its running context.
func (*Panic) LessT ¶ added in v0.26.0
LessT implements BV interface. It is not used in practice for panics.
func (*Panic) Matches ¶ added in v0.26.0
Matches implements BV interface. It is not used in practice for panics.
func (*Panic) Type ¶ added in v0.26.0
Type implements BV interface. It is not used in practice for panics.
func (*Panic) WithPrefix ¶ added in v0.26.0
WithPrefix adds a prefix to the error message and returns the modified Panic value. It creates a wrapped error using the %w format verb.
type R ¶ added in v0.41.0
type R struct {
// contains filtered or unexported fields
}
R represents a regular expression as created by the rx builtin.
func (*R) Append ¶ added in v0.41.0
Append appends a unique program representation of the value to dst, and returns the extended buffer.
type S ¶
type S string
S represents an immutable string of bytes.
func (S) Append ¶ added in v0.6.0
Append appends a unique program representation of the value to dst, and returns the extended buffer.
func (S) MarshalJSON ¶ added in v0.25.0
MarshalJSON implements json.Marshaler.
type V ¶
type V struct {
// contains filtered or unexported fields
}
V contains a generic boxed or unboxed value.
func Apply2FloatFunc ¶ added in v0.37.0
Apply2FloatFunc dyadically applies float math function. It returns a panic on error using MATHDYAD as operator template name in prefix. Its purpose is the same as ApplyFloatFunc, but for math functions taking two floats as arguments.
Within a variadic function, taking math.Pow as example, code using Apply2FloatFunc will typically look as follows:
r := goal.Apply2FloatFunc(x, y, math.Pow) if r.IsPanic() { return goal.NewPanic(strings.ReplaceAll(r.Panic().Error(), "MATHDYAD", "pow")) } return r
func ApplyFloatFunc ¶ added in v0.37.0
ApplyFloatFunc monadically applies float math function. It returns a panic on error without prefix. It can be used when more flexibility than provided by MonadicFloatFunc is needed.
Within a variadic function, taking math.Gamma as example, code using ApplyFloatFunc will typically look as follows:
r := goal.ApplyFloatFunc(x, math.Gamma) if r.IsPanic() { return goal.NewPanicV(r.Panic().WithPrefix("gamma :")) } return r
func NewAV ¶
NewAV returns a new array from a slice of generic values. The result value will be an array in canonical form. If the values are all of the same specialized type, like integers, floats, or strings, the underlying array will use a specialized representation, instead of a generic one.
It is the same as NewArray, but returns a generic value instead of an Array value.
func NewD ¶ added in v0.19.0
NewD returns a dictionary. Both keys and values should be arrays, and they should have the same length.
It is the same as NewDict, but with generic value inputs instead of Array values.
func NewDict ¶ added in v0.5.0
NewDict returns a dictionary. Both keys and values should have the same length.
It is the same as NewD, but with Array inputs instead of generic values.
func NewGap ¶ added in v0.41.0
func NewGap() V
NewGap returns a new gap value. It is the same as the zero value for type V.
The NewGap function is mostly meant to be used when building projections with NewProjection.
Note that gap values are not meant to be used explicitly from Goal code. Gap values are values generated and used by the interpreter to signal missing data in a few contexts:
- They are used to represent implicit non-fixed arguments in projections.
- They are the default value of undefined globals.
- They are returned by Run and Eval when code did not end returning a value.
Assigning a gap value with AssignGlobal can be used as a means of un-assigning a global, to make any ulterior attempt of using it panic.
func NewPanicError ¶ added in v0.26.0
NewPanicError returns a new panic value from given error. If the error is already of type *Panic any underlying location information is preserved.
func NewProjection ¶ added in v0.30.0
NewProjection returns a projection of x (usually a function) with the given arguments (in stack order). Gap values in args represent non-fixed arguments.
func (V) Append ¶ added in v0.6.0
Append appends a unique program representation of the value to dst, and returns the extended buffer.
func (V) Apply ¶ added in v0.24.0
Apply calls a value with one or more arguments. The arguments should be provided in stack order, as in the right to left semantics used by the language: the first argument is the last element.
func (V) BV ¶ added in v0.19.0
BV retrieves the boxed value, or nil if the value is not boxed. You can check whether the value is boxed with x.IsBV().
func (V) IsBV ¶ added in v0.19.0
IsBV reports whether the value is a boxed value satisfying the BV interface. You can retrieve the underlying boxed value with the BV method.
func (V) IsCallable ¶ added in v0.10.0
IsCallable reports whether the value can be called with one or more arguments. This is true for most values, including non-function ones.
func (V) IsFalse ¶ added in v0.10.0
IsFalse returns true for 0, 0i, -0w, 0n, "", rx//, (:), zero-length values, and errors.
func (V) IsFunction ¶
IsFunction reports whether the value is some kind of built-in function type, like verbs, adverbs, lambdas and projections. Type returns "f" for such values.
func (V) IsProjection ¶ added in v0.30.0
IsProjection reports whether x is a projection.
func (V) IsTrue ¶ added in v0.10.0
IsTrue returns false for 0, 0i, -0w, 0n, "", rx//, (:), zero-length values, and errors.
func (V) LessT ¶ added in v0.10.0
LessT reports whether x is ordered before y. It represents a strict total order. Values are ordered as follows: unboxed atoms first (numbers with NaNs first, variadics, then lambdas), then boxed values. Otherwise, values are compared with < and > when comparable, and otherwise using their Type string value. As a special case, comparable arrays are compared first by length, or lexicographically if they are of equal length.
func (V) MarkImmutable ¶ added in v0.19.0
func (x V) MarkImmutable()
MarkImmutable marks the value as definitively non-reusable. You can use this method to tell the optimizer that it cannot reuse its memory anymore. In particular, you should call this method before storing a value within a user-defined boxed value type.
func (V) MarshalJSON ¶ added in v0.25.0
MarshalJSON implements json.Marshaler. Note that not all generic values can be marshalled, only unboxed integers and floats, as well as boxed values implementing json.Marshaler. The json builtin in Goal is more tolerant and stringifies others kinds of values before encoding.
func (V) Rank ¶
Rank returns the value's rank (default arity). It returns 0 for non-function values. Rank is used in lambda partial application and in some adverbial expressions: see the FAQ's “How does function rank work?” question for details. Currently, ranks are as follows:
monad 1 dyad 2 lambda number of arguments projections number of gaps derived verb depends on the verb and adverb
type VariadicFunc ¶ added in v0.42.0
VariadicFunc represents a variadic function. The slice of arguments is in stack order: the first argument is the last element.
Most Context methods are available for use in variadic functions, except the ones that could affect the current execution state (Compile, Run, Eval).
See RegisterMonad and RegisterDyad for defining new variadic builtins usable from Goal.
func MonadicFloatFunc ¶ added in v0.31.0
func MonadicFloatFunc(name string, f func(float64) float64) VariadicFunc
MonadicFloatFunc returns a new variadic function for a given single-argument floating point math function. The name argument is used in error messages and is usually a monadic keyword. It can be used to easily register new monadic math functions, like for example:
ctx.RegisterMonad("gamma", goal.MonadicFloatFunc("gamma", math.Gamma))
Source Files ¶
- adverbs.go
- adverbspecial.go
- amend.go
- amendspecial.go
- apply.go
- arithd.go
- arithm.go
- arrays.go
- ast.go
- cmpsearch.go
- compiler.go
- context.go
- csv.go
- dicts.go
- encdec.go
- errors.go
- fills.go
- flip.go
- fns.go
- functions.go
- group.go
- join.go
- json.go
- less.go
- math.go
- norm.go
- opcode.go
- parser.go
- parsev.go
- radix.go
- rand.go
- refcount.go
- regexp.go
- rt.go
- sfns.go
- sort.go
- stringer.go
- strings.go
- time.go
- utf8.go
- utils.go
- valstring.go
- value.go
- variadics.go
- vm.go
Directories ¶
Path | Synopsis |
---|---|
Package cmd provides a quick way to create derived interpreters.
|
Package cmd provides a quick way to create derived interpreters. |
Package os provides variadic function definitions for IO/OS builtins.
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Package os provides variadic function definitions for IO/OS builtins. |
Package scan implements a scanner for Goal source text.
|
Package scan implements a scanner for Goal source text. |
html
Package html provides a simple html highlighter for Goal code working at the token level.
|
Package html provides a simple html highlighter for Goal code working at the token level. |