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e556fc3048
* Add packaged functions support * Add tests for math.floor func * Export FunctionsTable * Extract func stuff into its own package * Rename stuff * Fix tests * Move doc package to cmd/genji * Adjust naming, typos
76 lines
1.9 KiB
Go
76 lines
1.9 KiB
Go
package functions
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import (
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"strings"
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"github.com/genjidb/genji/internal/expr"
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"github.com/genjidb/genji/internal/stringutil"
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)
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// A Definition transforms a list of expressions into a Function.
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type Definition interface {
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Name() string
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String() string
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Function(...expr.Expr) (expr.Function, error)
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Arity() int
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}
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// Definitions table holds a map of definition, indexed by their names.
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type Definitions map[string]Definition
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// Packages represent a table of SQL functions grouped by their packages
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type Packages map[string]Definitions
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func DefaultPackages() Packages {
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return Packages{
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"": BuiltinDefinitions(),
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"math": MathFunctions(),
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}
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}
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// GetFunc return a function definition by its package and name.
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func (t Packages) GetFunc(pkg string, fname string) (Definition, error) {
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fs, ok := t[pkg]
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if !ok {
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return nil, stringutil.Errorf("no such package: %q", fname)
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}
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def, ok := fs[strings.ToLower(fname)]
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if !ok {
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if pkg == "" {
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return nil, stringutil.Errorf("no such function: %q", fname)
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}
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return nil, stringutil.Errorf("no such function: %q.%q", pkg, fname)
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}
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return def, nil
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}
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// A definition is the most basic version of a function definition.
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type definition struct {
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name string
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arity int
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constructorFn func(...expr.Expr) (expr.Function, error)
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}
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func (fd *definition) Name() string {
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return fd.name
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}
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func (fd *definition) Function(args ...expr.Expr) (expr.Function, error) {
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if len(args) != fd.arity {
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return nil, stringutil.Errorf("%s() takes %d argument(s), not %d", fd.name, fd.arity, len(args))
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}
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return fd.constructorFn(args...)
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}
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func (fd *definition) String() string {
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args := make([]string, 0, fd.arity)
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for i := 0; i < fd.arity; i++ {
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args = append(args, stringutil.Sprintf("arg%d", i+1))
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}
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return stringutil.Sprintf("%s(%s)", fd.name, strings.Join(args, ", "))
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}
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func (fd *definition) Arity() int {
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return fd.arity
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}
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