Documentation
¶
Overview ¶
Package wile provides the public API for embedding the Wile Scheme interpreter.
Basic usage:
engine, err := wile.NewEngine(ctx)
if err != nil {
log.Fatal(err)
}
result, err := engine.Eval(ctx, engine.MustParse(ctx, "(+ 1 2 3)"))
fmt.Println(result) // 6
With extensions:
engine, err := wile.NewEngine(ctx,
wile.WithExtension(io.Extension),
wile.WithExtension(system.Extension),
)
Sandboxed engine (no filesystem, eval, system, or Go interop):
engine, err := wile.NewEngine(ctx, wile.WithSafeExtensions())
Custom primitives:
engine, _ := wile.NewEngine(ctx)
engine.RegisterPrimitive(wile.PrimitiveSpec{
Name: "my-func",
ParamCount: 1,
Impl: myFuncImpl,
})
Index ¶
- Constants
- Variables
- func IsBoolean(v Value) bool
- func IsList(v Value) bool
- func IsNull(v Value) bool
- func IsNumber(v Value) bool
- func IsPair(v Value) bool
- func IsProcedure(v Value) bool
- func IsString(v Value) bool
- func IsSymbol(v Value) bool
- func NewNamespace(ctx context.Context, opts ...EngineOption) (*environment.Namespace, error)
- func ToGoBool(v Value) (bool, bool)
- func ToGoFloat(v Value) (float64, bool)
- func ToGoInt(v Value) (int64, bool)
- func ToGoString(v Value) (string, bool)
- type CompilationError
- type CompiledCode
- type Engine
- func (p *Engine) Call(ctx context.Context, proc Value, args ...Value) (Value, error)
- func (p *Engine) Close() error
- func (p *Engine) Compile(ctx context.Context, expr *Expression) (*CompiledCode, error)
- func (p *Engine) CurrentLoadDirectory() string
- func (p *Engine) CurrentLoadPath() string
- func (p *Engine) Define(name string, value Value) error
- func (p *Engine) Environment() *environment.EnvironmentFrame
- func (p *Engine) Eval(ctx context.Context, expr *Expression) (Value, error)
- func (p *Engine) EvalIn(ctx context.Context, expr *Expression, ns *environment.Namespace) (Value, error)
- func (p *Engine) EvalMultiple(ctx context.Context, code string) (Value, error)
- func (p *Engine) EvalMultipleWithSource(ctx context.Context, code string, source string) (Value, error)
- func (p *Engine) Get(name string) (Value, bool)
- func (p *Engine) LastCounters() machine.VMCounters
- func (p *Engine) MustParse(ctx context.Context, code string) *Expression
- func (p *Engine) MustParseWithSource(ctx context.Context, code string, source string) *Expression
- func (p *Engine) Namespace() *environment.Namespace
- func (p *Engine) Parse(ctx context.Context, code string) (*Expression, error)
- func (p *Engine) ParseWithSource(ctx context.Context, code string, source string) (*Expression, error)
- func (p *Engine) PopLoadPath()
- func (p *Engine) PushLoadPath(filePath string) error
- func (p *Engine) RegisterFunc(name string, fn any) error
- func (p *Engine) RegisterFuncs(funcs map[string]any) error
- func (p *Engine) RegisterPrimitive(spec PrimitiveSpec) error
- func (p *Engine) Registry() *registry.Registry
- func (p *Engine) Run(ctx context.Context, cc *CompiledCode) (Value, error)
- func (p *Engine) WithLoadPath(filePath string, fn func() error) error
- type EngineOption
- func AllExtensions() []EngineOption
- func SafeExtensions() []EngineOption
- func WithAllExtensions() EngineOption
- func WithAuthorizer(auth security.Authorizer) EngineOption
- func WithExtension(ext registry.Extension) EngineOption
- func WithExtensions(exts ...registry.Extension) EngineOption
- func WithImportObserver(obs func(LibraryImportEvent)) EngineOption
- func WithLibraryPaths(paths ...string) EngineOption
- func WithMaxCallDepth(n uint64) EngineOption
- func WithNamespace(ns *environment.Namespace) EngineOption
- func WithRegistry(r *registry.Registry) EngineOption
- func WithSafeExtensions() EngineOption
- func WithSourceFS(fsys fs.FS) EngineOption
- func WithSourceOS() EngineOption
- func WithoutCore() EngineOption
- type Expression
- type ForeignFunction
- type LibraryImportEvent
- type MachineContext
- type PrimitiveSpec
- type RuntimeError
- type Value
- func Car(v Value) (Value, bool)
- func Cdr(v Value) (Value, bool)
- func NewBigFloat(f *big.Float) Value
- func NewBigFloatFromFloat64(f float64) Value
- func NewBigFloatFromString(s string) Value
- func NewBigInteger(n *big.Int) Value
- func NewBigIntegerFromInt64(n int64) Value
- func NewBigIntegerFromString(s string, base int) Value
- func NewBoolean(b bool) Value
- func NewComplex(v complex128) Value
- func NewComplexFromParts(realPart, imagPart float64) Value
- func NewFloat(f float64) Value
- func NewInteger(n int64) Value
- func NewList(vals ...Value) Value
- func NewRational(num, denom int64) Value
- func NewRationalFromBigInt(num, denom *big.Int) Value
- func NewString(s string) Value
- func NewSymbol(s string) Value
- func NewVector(vals ...Value) Value
- func ToSlice(ctx context.Context, v Value) ([]Value, bool)
Examples ¶
Constants ¶
const ( PhaseExpand = environment.PhaseExpand PhaseCompile = environment.PhaseCompile )
Phase constants for LibraryImportEvent.Phase. Re-exported from environment for embedder convenience.
const DefaultMaxCallDepth uint64 = 10000
DefaultMaxCallDepth is the default call depth limit for new engines. At ~500 bytes per frame, 10000 frames ≈ 5MB. Use WithMaxCallDepth(0) to opt out of the limit explicitly.
Variables ¶
var EmptyList = wrapValue(values.EmptyList)
EmptyList is the empty list.
var ErrEngineClosed = werr.NewStaticError("engine is closed")
ErrEngineClosed is returned when Close is called on an already-closed engine.
var False = wrapValue(values.FalseValue)
False is the #f value.
var StdLibFS = mustSub(stdlibRaw, "stdlib")
StdLibFS provides the standard Scheme libraries shipped with wile (e.g., (wile algebra), (wile match), etc.) as an embedded filesystem. The filesystem is rooted at stdlib/, so library paths resolve as "lib/...". Consumers add it to the engine with WithSourceFS(StdLibFS).
var True = wrapValue(values.TrueValue)
True is the #t value.
var Void = wrapValue(values.Void)
Void is the void value.
Functions ¶
func IsPair ¶ added in v1.1.0
IsPair returns true if v is a non-empty pair (cons cell). EmptyList is not a *Pair (it's a separate type), so the type assertion handles the distinction without an explicit IsEmptyList check.
func IsProcedure ¶ added in v1.1.0
IsProcedure returns true if v is a callable procedure (lambda, foreign closure, case-lambda, parameter, or composable continuation).
func NewNamespace ¶ added in v1.7.0
func NewNamespace(ctx context.Context, opts ...EngineOption) (*environment.Namespace, error)
NewNamespace creates a fully initialized namespace with a registry, base environment bindings, syntax compilers, expanders, and bootstrap macros. The namespace can be passed to NewEngine via WithNamespace.
Options are shared with NewEngine: WithExtension, WithRegistry, WithoutCore, WithAuthorizer all work. Engine-specific options (WithMaxCallDepth, WithLibraryPaths, etc.) are accepted but ignored.
Example:
ns, err := wile.NewNamespace(ctx,
wile.WithExtension(math.Extension),
wile.WithAuthorizer(security.ReadOnly()),
)
eng, err := wile.NewEngine(ctx, wile.WithNamespace(ns))
func ToGoBool ¶ added in v1.1.0
ToGoBool extracts a Go bool from a Scheme boolean value. Returns (false, false) if v is not a boolean.
func ToGoFloat ¶ added in v1.1.0
ToGoFloat extracts a float64 from an inexact real value. Returns (0, false) if v is not a Float.
func ToGoInt ¶ added in v1.1.0
ToGoInt extracts an int64 from an exact integer value. Returns (0, false) if v is not an exact integer or does not fit in int64.
func ToGoString ¶ added in v1.1.0
ToGoString extracts the Go string from a Scheme string value. Returns ("", false) if v is not a string.
Types ¶
type CompilationError ¶ added in v1.1.0
CompilationError wraps errors from parsing, expanding, or compiling Scheme code.
func (*CompilationError) Error ¶ added in v1.1.0
func (p *CompilationError) Error() string
func (*CompilationError) Unwrap ¶ added in v1.1.0
func (p *CompilationError) Unwrap() error
type CompiledCode ¶
type CompiledCode struct {
// contains filtered or unexported fields
}
CompiledCode represents compiled Scheme code ready for execution.
CompiledCode captures the environment from the Engine that compiled it and always executes using that captured environment, regardless of which Engine is used to run it. Using a different Engine instance affects only that Engine's own bookkeeping (for example, evaluation counters), not the environment bindings or symbol interning.
CompiledCode can be run multiple times. It is not safe for concurrent execution (the underlying Engine is not goroutine-safe).
func (*CompiledCode) String ¶
func (p *CompiledCode) String() string
String returns a string representation of the compiled code.
type Engine ¶
type Engine struct {
// contains filtered or unexported fields
}
Engine is the main entry point for embedding Wile.
An Engine is NOT safe for concurrent use from multiple goroutines. Most methods that parse, compile, or evaluate code mutate the environment. Each goroutine should use its own Engine, or synchronize externally.
SRFI-18 threads within a single Engine are safe — the VM handles thread coordination internally.
func NewEngine ¶
func NewEngine(ctx context.Context, opts ...EngineOption) (*Engine, error)
NewEngine creates a new Wile engine. By default, only core primitives are included. Use WithExtension to add optional extensions.
When WithNamespace is used, the engine uses the pre-built namespace and ignores registry/extension/core options (they were applied when the namespace was created). Library paths and other engine-specific options still apply.
Example ¶
package main
import (
"context"
"fmt"
"log"
"github.com/aalpar/wile"
)
func main() {
engine, err := wile.NewEngine(context.Background())
if err != nil {
log.Fatal(err)
}
ctx := context.Background()
result, err := engine.Eval(ctx, engine.MustParse(ctx, "(+ 1 2 3)"))
if err != nil {
log.Fatal(err)
}
fmt.Println(result.SchemeString())
}
Output: 6
Example (WithExtension) ¶
package main
import (
"context"
"fmt"
"log"
"github.com/aalpar/wile"
"github.com/aalpar/wile/internal/extensions/io"
)
func main() {
_, err := wile.NewEngine(context.Background(),
wile.WithExtension(io.Extension),
)
if err != nil {
log.Fatal(err)
}
fmt.Println("engine created with I/O extension")
}
Output: engine created with I/O extension
func (*Engine) Call ¶
Call invokes a Scheme procedure with arguments. Supports lambdas, foreign closures, case-lambdas, and parameters. Composable continuations cannot be called from Go (they require the VM winding stack) and return an error.
Example ¶
package main
import (
"context"
"fmt"
"log"
"github.com/aalpar/wile"
)
func main() {
engine, err := wile.NewEngine(context.Background())
if err != nil {
log.Fatal(err)
}
// Define a Scheme function.
ctx := context.Background()
_, err = engine.EvalMultiple(ctx, `
(define (square x) (* x x))
`)
if err != nil {
log.Fatal(err)
}
// Retrieve and call it from Go.
proc, ok := engine.Get("square")
if !ok {
log.Fatal("square not found")
}
result, err := engine.Call(ctx, proc, wile.NewInteger(12))
if err != nil {
log.Fatal(err)
}
fmt.Println(result.SchemeString())
}
Output: 144
func (*Engine) Close ¶ added in v1.3.0
Close releases resources held by closeable extensions. Extensions that implement registry.Closeable have their Close method called. Errors from individual closers are collected and returned via errors.Join. Calling Close on an already-closed engine returns ErrEngineClosed.
func (*Engine) Compile ¶
func (p *Engine) Compile(ctx context.Context, expr *Expression) (*CompiledCode, error)
Compile compiles a parsed expression without executing. The result can be executed later with Engine.Run.
Example ¶
package main
import (
"context"
"fmt"
"log"
"github.com/aalpar/wile"
)
func main() {
engine, err := wile.NewEngine(context.Background())
if err != nil {
log.Fatal(err)
}
// Define a variable, then compile an expression that uses it.
ctx := context.Background()
_, err = engine.Eval(ctx, engine.MustParse(ctx, "(define x 0)"))
if err != nil {
log.Fatal(err)
}
compiled, err := engine.Compile(context.Background(), engine.MustParse(context.Background(), "(* x x)"))
if err != nil {
log.Fatal(err)
}
// Run the same compiled code with different values of x.
for _, n := range []int64{3, 5, 7} {
err = engine.Define("x", wile.NewInteger(n))
if err != nil {
log.Fatal(err)
}
result, err := engine.Run(ctx, compiled)
if err != nil {
log.Fatal(err)
}
fmt.Println(result.SchemeString())
}
}
Output: 9 25 49
func (*Engine) CurrentLoadDirectory ¶ added in v1.3.0
CurrentLoadDirectory returns the directory of the file currently being loaded, or empty string if no file is being loaded.
func (*Engine) CurrentLoadPath ¶ added in v1.3.0
CurrentLoadPath returns the path of the file currently being loaded, or empty string if no file is being loaded.
func (*Engine) Define ¶
Define binds a value to a name in the top-level environment.
Example ¶
package main
import (
"context"
"fmt"
"log"
"github.com/aalpar/wile"
)
func main() {
engine, err := wile.NewEngine(context.Background())
if err != nil {
log.Fatal(err)
}
err = engine.Define("width", wile.NewInteger(800))
if err != nil {
log.Fatal(err)
}
err = engine.Define("height", wile.NewInteger(600))
if err != nil {
log.Fatal(err)
}
ctx := context.Background()
result, err := engine.Eval(ctx, engine.MustParse(ctx, "(* width height)"))
if err != nil {
log.Fatal(err)
}
fmt.Println(result.SchemeString())
}
Output: 480000
func (*Engine) Environment ¶
func (p *Engine) Environment() *environment.EnvironmentFrame
Environment returns the underlying environment for advanced use.
func (*Engine) Eval ¶
Eval compiles and executes a parsed expression, returning the result. Use Engine.Parse to obtain an Expression from source code. For evaluating multi-expression strings, use Engine.EvalMultiple.
func (*Engine) EvalIn ¶ added in v1.7.0
func (p *Engine) EvalIn(ctx context.Context, expr *Expression, ns *environment.Namespace) (Value, error)
EvalIn compiles and executes a parsed expression in the given namespace, rather than the engine's own namespace.
The target namespace's authorizer governs security checks during execution. If the target namespace has no authorizer, the engine's authorizer is propagated to it before evaluation.
func (*Engine) EvalMultiple ¶
EvalMultiple evaluates multiple expressions, returning the last result.
Example ¶
package main
import (
"context"
"fmt"
"log"
"github.com/aalpar/wile"
)
func main() {
engine, err := wile.NewEngine(context.Background())
if err != nil {
log.Fatal(err)
}
ctx := context.Background()
result, err := engine.EvalMultiple(ctx, `
(define x 10)
(define y 20)
(+ x y)
`)
if err != nil {
log.Fatal(err)
}
fmt.Println(result.SchemeString())
}
Output: 30
func (*Engine) EvalMultipleWithSource ¶ added in v1.1.0
func (p *Engine) EvalMultipleWithSource(ctx context.Context, code string, source string) (Value, error)
EvalMultipleWithSource evaluates multiple expressions, returning the last result. The source parameter identifies where the code came from (e.g. a filename) and appears in error messages and stack traces.
func (*Engine) LastCounters ¶ added in v1.1.0
func (p *Engine) LastCounters() machine.VMCounters
LastCounters returns the VM performance counters from the most recent Run or Eval call. Sub-context counters are not aggregated.
func (*Engine) MustParse ¶ added in v1.8.0
func (p *Engine) MustParse(ctx context.Context, code string) *Expression
MustParse is like Parse but panics on error.
func (*Engine) MustParseWithSource ¶ added in v1.8.0
MustParseWithSource is like ParseWithSource but panics on error.
func (*Engine) Namespace ¶ added in v1.7.0
func (p *Engine) Namespace() *environment.Namespace
Namespace returns the Namespace for advanced use. This provides access to per-instance symbol interning and phase management.
func (*Engine) Parse ¶ added in v1.8.0
Parse parses a single Scheme expression from code.
Parse returns a CompilationError if the input is empty, malformed, or contains more than one expression.
func (*Engine) ParseWithSource ¶ added in v1.8.0
func (p *Engine) ParseWithSource(ctx context.Context, code string, source string) (*Expression, error)
ParseWithSource parses a single Scheme expression from code. The source parameter identifies where the code came from (e.g. a filename) and appears in error messages.
func (*Engine) PopLoadPath ¶ added in v1.3.0
func (p *Engine) PopLoadPath()
PopLoadPath removes the top path from the load path stack. Does nothing if the stack is empty.
Advanced embedders who need fine-grained control can use Push/Pop directly, but most should use WithLoadPath for automatic cleanup.
func (*Engine) PushLoadPath ¶ added in v1.3.0
PushLoadPath pushes a path onto the load path stack. Returns an error if the path is empty.
Advanced embedders who need fine-grained control can use Push/Pop directly, but most should use WithLoadPath for automatic cleanup.
func (*Engine) RegisterFunc ¶ added in v1.1.0
RegisterFunc registers a Go function as a Scheme primitive using natural Go signatures.
Reflection-based FFI bridging: pre-computes argument and return converters at registration time using Go's reflect package. Each call uses the cached converters to translate between Scheme values and Go types, avoiding per-call reflection overhead. See BIBLIOGRAPHY.md "Reflection-Based FFI Bridging".
Supported Types ¶
Parameter types: int64, int, float64, string, bool, []byte, []T (typed slices), map[K]V, structs (exported fields), func(...) (callbacks), Value, and context.Context (first param only).
Return types: int64, int, float64, string, bool, []byte, []T, map[K]V, structs, Value, error (last return only), and void.
Variadic Functions ¶
Variadic Go functions are supported. The variadic parameter receives all excess arguments from Scheme, converted element-by-element.
Context Forwarding ¶
If the first parameter is context.Context, the VM's context is forwarded automatically and does not count toward the Scheme parameter count.
Callbacks ¶
Callback parameters (func types) receive a Go closure that invokes a Scheme procedure through a VM sub-context. Callbacks must be called synchronously during the registered function's execution. Storing a callback for later invocation or calling it from another goroutine is unsafe — the closure captures VM state that is not goroutine-safe.
Returns an error wrapping werr.ErrFFIRegistration if fn is not a function or uses unsupported types.
Example ¶
package main
import (
"context"
"fmt"
"log"
"github.com/aalpar/wile"
)
func main() {
engine, err := wile.NewEngine(context.Background())
if err != nil {
log.Fatal(err)
}
// Register a Go function with a natural signature — no MachineContext needed.
err = engine.RegisterFunc("double", func(n int64) int64 {
return n * 2
})
if err != nil {
log.Fatal(err)
}
ctx := context.Background()
result, err := engine.Eval(ctx, engine.MustParse(ctx, "(map double '(1 2 3 4 5))"))
if err != nil {
log.Fatal(err)
}
fmt.Println(result.SchemeString())
}
Output: (2 4 6 8 10)
func (*Engine) RegisterFuncs ¶ added in v1.4.0
RegisterFuncs registers multiple Go functions as Scheme primitives. Each key in the map is the Scheme name; each value must be a Go function with a signature supported by [RegisterFunc].
Registration stops on the first error. The error message includes the binding name that failed first. When multiple functions are invalid, the particular binding that fails first is non-deterministic because Go map iteration order is unspecified. Functions registered before the failure remain registered.
func (*Engine) RegisterPrimitive ¶
func (p *Engine) RegisterPrimitive(spec PrimitiveSpec) error
RegisterPrimitive adds a Go function as a Scheme primitive.
Example ¶
package main
import (
"context"
"fmt"
"log"
"github.com/aalpar/wile"
"github.com/aalpar/wile/values"
)
func main() {
engine, err := wile.NewEngine(context.Background())
if err != nil {
log.Fatal(err)
}
// Register a Go function that doubles an integer.
err = engine.RegisterPrimitive(wile.PrimitiveSpec{
Name: "double",
ParamCount: 1,
Impl: func(mc *wile.MachineContext) error {
n := mc.Arg(0).(*values.Integer).Value
mc.SetValue(values.NewInteger(n * 2))
return nil
},
})
if err != nil {
log.Fatal(err)
}
ctx := context.Background()
result, err := engine.Eval(ctx, engine.MustParse(ctx, "(double 21)"))
if err != nil {
log.Fatal(err)
}
fmt.Println(result.SchemeString())
}
Output: 42
func (*Engine) Registry ¶ added in v1.5.0
Registry returns a clone of the engine's registry. The returned registry can be filtered with Without, WithoutCategory, or WithoutBindings and passed to NewEngine via WithRegistry to create a restricted engine.
func (*Engine) WithLoadPath ¶ added in v1.3.0
WithLoadPath executes fn with filePath pushed onto the load path stack. This is the recommended API for embedders — it guarantees balanced push/pop via defer even if fn panics or returns an error.
Returns an error if filePath is empty.
Example:
err := engine.WithLoadPath("/app/scripts/main.scm", func() error {
_, err := engine.EvalMultiple(ctx, "(load \"helper.scm\")") // resolves relative to /app/scripts/
return err
})
type EngineOption ¶
type EngineOption func(*engineConfig)
EngineOption configures an Engine.
func AllExtensions ¶ added in v1.9.7
func AllExtensions() []EngineOption
AllExtensions returns the complete set of engine options that add every available extension. This matches the extension set loaded by the CLI binary (io, files, math, introspection, eval, namespace, threads, gointerop, all, system).
Use WithAllExtensions when no additional options need to be appended.
Example:
eng, err := wile.NewEngine(ctx,
append(wile.AllExtensions(),
wile.WithLibraryPaths("./stdlib/lib"),
)...,
)
func SafeExtensions ¶ added in v1.5.0
func SafeExtensions() []EngineOption
SafeExtensions returns engine options that add extensions suitable for sandboxed engines: io, exceptions, math, introspection, and the safe subset of all (records, promises, strings, characters).
These provide R7RS functionality without filesystem, eval, system, Go interop, or threading access. Core primitives are still added by default unless WithoutCore is also used.
Principle of Least Authority (Saltzer & Schroeder 1975).
authority(engine) = ∪ { caps(ext) : ext ∈ extensions }
SafeExtensions() ⊂ AllExtensions() — the safe set excludes
filesystem, eval, system, Go interop, and threading capabilities.
WithoutCore() produces authority(engine) = ∅.
Invariant: absent capabilities produce compile-time errors, not
runtime checks. If a name has no binding, compilation fails.
No runtime check can be bypassed because no runtime check exists.
Constrains: NewEngine (applies the registry), LibraryEnvFactory
(closes over registry — transitive confinement per Lampson 1973).
Constrained by: Registry.Without/WithoutCategory (capability
attenuation — derived registries never gain authority).
See BIBLIOGRAPHY.md "Saltzer & Schroeder".
Example:
eng, err := wile.NewEngine(ctx,
append(wile.SafeExtensions(),
wile.WithLibraryPaths("./stdlib/lib"),
)...,
)
func WithAllExtensions ¶ added in v1.9.7
func WithAllExtensions() EngineOption
WithAllExtensions adds every available extension to the engine. This is a convenience wrapper around AllExtensions for the common case where no additional options need to be appended.
Example:
eng, err := wile.NewEngine(ctx, wile.WithAllExtensions())
func WithAuthorizer ¶ added in v1.5.0
func WithAuthorizer(auth security.Authorizer) EngineOption
WithAuthorizer sets the Authorizer for the engine. The authorizer is injected into every context passed to Eval, Compile, Run, and Call, gating runtime primitives and compile-time code loading.
Without this option, all operations are allowed (open by default). The authorizer is immutable after engine construction.
Example:
eng, err := wile.NewEngine(ctx,
wile.WithAuthorizer(security.ReadOnly()),
)
func WithExtension ¶
func WithExtension(ext registry.Extension) EngineOption
WithExtension adds an extension to the engine.
func WithExtensions ¶
func WithExtensions(exts ...registry.Extension) EngineOption
WithExtensions adds multiple extensions to the engine.
func WithImportObserver ¶ added in v1.5.0
func WithImportObserver(obs func(LibraryImportEvent)) EngineOption
WithImportObserver sets a callback that is invoked each time a library is imported. The observer is read-only — it cannot influence the import. Requires WithLibraryPaths to be effective (no libraries loaded without it).
func WithLibraryPaths ¶ added in v1.4.0
func WithLibraryPaths(paths ...string) EngineOption
WithLibraryPaths enables the R7RS library system (define-library / import) and configures directories to search for .sld library files.
Without this option, (import ...) raises a configuration error.
Paths are searched in order: user-supplied paths first, then the defaults ("." and "./stdlib/lib"). An empty call WithLibraryPaths() enables library support with defaults only.
Example:
eng, err := wile.NewEngine(ctx,
wile.WithLibraryPaths("/app/libs", "./vendor"),
)
// search order: /app/libs, ./vendor, ., ./stdlib/lib
func WithMaxCallDepth ¶ added in v1.3.0
func WithMaxCallDepth(n uint64) EngineOption
WithMaxCallDepth sets the maximum recursion depth for the VM. When the continuation stack exceeds this depth, ErrCallDepthExceeded is returned. A value of 0 means unlimited (no depth check). When not called, the engine uses DefaultMaxCallDepth (10000).
func WithNamespace ¶ added in v1.7.0
func WithNamespace(ns *environment.Namespace) EngineOption
WithNamespace uses a pre-built namespace instead of building one from extension options. When set, registry/extension/core options are ignored by NewEngine (they were already applied when the namespace was created).
This enables sharing a namespace across engines or pre-configuring namespaces with specific capabilities.
func WithRegistry ¶
func WithRegistry(r *registry.Registry) EngineOption
WithRegistry uses a custom registry instead of the default. When set, core primitives are NOT automatically added.
func WithSafeExtensions ¶ added in v1.5.0
func WithSafeExtensions() EngineOption
WithSafeExtensions adds the safe extension set to the engine. This is a convenience wrapper around SafeExtensions for the common case where no additional options need to be appended.
Example:
eng, err := wile.NewEngine(ctx, wile.WithSafeExtensions())
func WithSourceFS ¶ added in v1.7.1
func WithSourceFS(fsys fs.FS) EngineOption
WithSourceFS adds a virtual filesystem layer to the source file resolver chain. Multiple calls add layers searched in call order. When no resolver options are used, the engine defaults to the OS filesystem. Once any resolver option is used (WithSourceFS or WithSourceOS), only the explicitly configured resolvers are active.
Bootstrap macros are unaffected — they always load from the embedded bootstrap filesystem.
Example:
//go:embed scheme
var schemeFS embed.FS
eng, err := wile.NewEngine(ctx,
wile.WithSourceFS(schemeFS), // searched first
wile.WithSourceOS(), // OS filesystem searched last
)
func WithSourceOS ¶ added in v1.7.2
func WithSourceOS() EngineOption
WithSourceOS adds the OS filesystem to the source file resolver chain. This is typically called last so that virtual filesystems are searched first. When no resolver options are used, the engine defaults to the OS filesystem; WithSourceOS is only needed when building an explicit chain with WithSourceFS.
Example:
eng, err := wile.NewEngine(ctx,
wile.WithSourceFS(embedFS), // virtual FS first
wile.WithSourceOS(), // OS fallback last
)
func WithoutCore ¶ added in v1.5.0
func WithoutCore() EngineOption
WithoutCore creates an engine with an empty registry — no core primitives (arithmetic, pairs, control flow, etc.) are added. Extensions added via WithExtension are still applied.
This is useful for building minimal engines where only specific extensions are needed, or for testing extension isolation.
type Expression ¶ added in v1.8.0
type Expression struct {
// contains filtered or unexported fields
}
Expression represents a single parsed Scheme expression.
Expression wraps a syntax value produced by the parser, before any macro expansion or compilation. It captures the source name (if any) for use in error messages.
Expression is not safe for concurrent use.
func (*Expression) Source ¶ added in v1.8.0
func (p *Expression) Source() string
Source returns the source name associated with this expression. Returns the empty string if no source was specified at parse time.
func (*Expression) String ¶ added in v1.8.0
func (p *Expression) String() string
String returns a string representation of the expression.
type ForeignFunction ¶
type ForeignFunction = machine.ForeignFunction
ForeignFunction is the signature for primitive implementations. This is a re-export of machine.ForeignFunction for convenience.
type LibraryImportEvent ¶ added in v1.5.0
type LibraryImportEvent = machine.LibraryImportEvent
LibraryImportEvent records what happened when a library was imported. See machine.LibraryImportEvent for field documentation.
type MachineContext ¶
type MachineContext = machine.MachineContext
MachineContext provides access to the VM during primitive execution. This is a re-export of machine.MachineContext for convenience.
type PrimitiveSpec ¶
type PrimitiveSpec = registry.PrimitiveSpec
PrimitiveSpec defines a primitive to be registered. This is a re-export of registry.PrimitiveSpec for convenience.
type RuntimeError ¶ added in v1.1.0
type RuntimeError struct {
Message string
Cause error
Condition Value // non-nil when Scheme raise produced the error; nil for VM/primitive errors
Source string // formatted source location ("file:line:col"), empty if unavailable
StackTrace string // formatted VM stack trace, empty if unavailable
}
RuntimeError wraps errors from executing Scheme code.
Condition ¶
When the error originated from a Scheme raise or raise-continuable, Condition holds the raised value and RuntimeError.IsSchemeException returns true. When the error originated from Go code (VM errors, primitive failures, type mismatches), Condition is nil.
Source and Stack Trace ¶
Source and StackTrace provide the source location and VM stack trace at the point of the error. Both are empty strings when per-operation source tracking is unavailable.
Cause ¶
Cause may contain internal machine types. Callers should treat it as an opaque error suitable for logging and errors.Is/errors.As matching, not for direct type inspection.
func (*RuntimeError) Error ¶ added in v1.1.0
func (p *RuntimeError) Error() string
func (*RuntimeError) IsSchemeException ¶ added in v1.3.0
func (p *RuntimeError) IsSchemeException() bool
IsSchemeException reports whether this error originated from a Scheme raise or raise-continuable expression. When true, Condition holds the raised value.
func (*RuntimeError) Unwrap ¶ added in v1.1.0
func (p *RuntimeError) Unwrap() error
type Value ¶
type Value interface {
// SchemeString returns the Scheme representation.
SchemeString() string
// IsVoid returns true if this is the void value.
IsVoid() bool
// Internal returns the underlying values.Value for advanced use.
// This is exported for use by testing packages and advanced embedding scenarios.
Internal() values.Value
// contains filtered or unexported methods
}
Value represents a Scheme value in the public API.
func Car ¶ added in v1.1.0
Car returns the car of a pair or other Tuple type. Returns (value, true) on success, or (nil, false) if v is not a non-empty Tuple.
func Cdr ¶ added in v1.1.0
Cdr returns the cdr of a pair or other Tuple type. Returns (value, true) on success, or (nil, false) if v is not a non-empty Tuple.
func NewBigFloat ¶
NewBigFloat creates a big float value from a big.Float.
func NewBigFloatFromFloat64 ¶
NewBigFloatFromFloat64 creates a big float value from a float64.
func NewBigFloatFromString ¶
NewBigFloatFromString creates a big float from a string. Returns nil if the string is not a valid float.
func NewBigInteger ¶
NewBigInteger creates a big integer value from a big.Int.
func NewBigIntegerFromInt64 ¶
NewBigIntegerFromInt64 creates a big integer value from an int64.
func NewBigIntegerFromString ¶
NewBigIntegerFromString creates a big integer from a string in the given base. Returns nil if the string is not a valid integer.
func NewComplex ¶ added in v1.2.0
func NewComplex(v complex128) Value
NewComplex creates a Scheme complex number from a Go complex128.
func NewComplexFromParts ¶ added in v1.2.0
NewComplexFromParts creates a Scheme complex number from real and imaginary parts.
func NewRational ¶ added in v1.2.0
NewRational creates a Scheme exact rational number.
func NewRationalFromBigInt ¶ added in v1.2.0
NewRationalFromBigInt creates a Scheme exact rational from big.Int numerator and denominator.
Source Files
¶
Directories
¶
| Path | Synopsis |
|---|---|
|
cmd
|
|
|
typeswitchlint
command
Command typeswitchlint finds type switch statements on values.Value or values.Number that may be missing cases for concrete types.
|
Command typeswitchlint finds type switch statements on values.Value or values.Number that may be missing cases for concrete types. |
|
wile
command
Package main provides the entry point for the Wile Scheme interpreter binary.
|
Package main provides the entry point for the Wile Scheme interpreter binary. |
|
Package environment provides variable binding and scoping for the Scheme compiler.
|
Package environment provides variable binding and scoping for the Scheme compiler. |
|
examples
|
|
|
embedding
command
basic demonstrates embedding the Wile Scheme interpreter in a Go program.
|
basic demonstrates embedding the Wile Scheme interpreter in a Go program. |
|
embedding/source-tracking
command
source-tracking demonstrates the ParseWithSource/MustParseWithSource API for embedding Wile with per-operation source location tracking.
|
source-tracking demonstrates the ParseWithSource/MustParseWithSource API for embedding Wile with per-operation source location tracking. |
|
extensions
|
|
|
files
Package files provides file I/O primitives.
|
Package files provides file I/O primitives. |
|
gointerop
Package gointerop provides Go concurrency primitive wrappers.
|
Package gointerop provides Go concurrency primitive wrappers. |
|
introspection
Package introspection provides read-only environment introspection primitives.
|
Package introspection provides read-only environment introspection primitives. |
|
math
Package math provides transcendental and advanced mathematical primitives.
|
Package math provides transcendental and advanced mathematical primitives. |
|
process
Package process provides subprocess execution primitives.
|
Package process provides subprocess execution primitives. |
|
system
Package system provides system interface primitives.
|
Package system provides system interface primitives. |
|
threads
Package threads provides SRFI-18 multithreading primitives.
|
Package threads provides SRFI-18 multithreading primitives. |
|
internal
|
|
|
bootstrap
Package bootstrap initializes the top-level Scheme environment.
|
Package bootstrap initializes the top-level Scheme environment. |
|
extensions/all
Package all provides additional primitives for records, promises, and extended string/character operations.
|
Package all provides additional primitives for records, promises, and extended string/character operations. |
|
extensions/eval
Package eval provides evaluation and environment primitives.
|
Package eval provides evaluation and environment primitives. |
|
extensions/io
Package io provides I/O primitives for reading and writing.
|
Package io provides I/O primitives for reading and writing. |
|
extensions/namespace
Package namespace provides namespace manipulation primitives.
|
Package namespace provides namespace manipulation primitives. |
|
forms
Package forms provides a unified registry for special form handlers.
|
Package forms provides a unified registry for special form handlers. |
|
match
Package match implements the pattern matching engine for syntax-rules and syntax-case.
|
Package match implements the pattern matching engine for syntax-rules and syntax-case. |
|
parser
Package parser implements R7RS Scheme syntax parsing.
|
Package parser implements R7RS Scheme syntax parsing. |
|
repl
Package repl provides an interactive Read-Eval-Print Loop for Wile Scheme.
|
Package repl provides an interactive Read-Eval-Print Loop for Wile Scheme. |
|
schemeutil
Package schemeutil provides conversion utilities between syntax, datum, and Go types.
|
Package schemeutil provides conversion utilities between syntax, datum, and Go types. |
|
syntax
Package syntax implements Scheme syntax representation with hygiene support.
|
Package syntax implements Scheme syntax representation with hygiene support. |
|
syntax/syntaxtest
Package syntaxtest provides test helpers for the syntax package.
|
Package syntaxtest provides test helpers for the syntax package. |
|
tokenizer
Package tokenizer implements R7RS Scheme lexical analysis.
|
Package tokenizer implements R7RS Scheme lexical analysis. |
|
validate
Package validate validates Scheme syntax and produces typed expressions.
|
Package validate validates Scheme syntax and produces typed expressions. |
|
Package machine implements the Scheme virtual machine, compiler, and macro expander.
|
Package machine implements the Scheme virtual machine, compiler, and macro expander. |
|
Package registry provides a plugin architecture for registering Scheme primitives.
|
Package registry provides a plugin architecture for registering Scheme primitives. |
|
core
Package core provides the essential primitives required for Scheme to function.
|
Package core provides the essential primitives required for Scheme to function. |
|
helpers
Package helpers provides shared utility functions for primitive implementations.
|
Package helpers provides shared utility functions for primitive implementations. |
|
testhelpers
Package testhelpers provides shared test infrastructure for Scheme primitive tests.
|
Package testhelpers provides shared test infrastructure for Scheme primitive tests. |
|
Package gorules defines custom lint rules for the Wile project.
|
Package gorules defines custom lint rules for the Wile project. |
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Package runtime provides the core API for embedding Wile Scheme in Go applications.
|
Package runtime provides the core API for embedding Wile Scheme in Go applications. |
|
Package security provides fine-grained authorization for Scheme runtime operations.
|
Package security provides fine-grained authorization for Scheme runtime operations. |
|
Package stdlib provides the embedded R7RS standard library files.
|
Package stdlib provides the embedded R7RS standard library files. |
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Package values implements all Scheme runtime value types.
|
Package values implements all Scheme runtime value types. |
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valuestest
Package valuestest provides test helpers for the values package.
|
Package valuestest provides test helpers for the values package. |