53 lines
1 KiB
Go
53 lines
1 KiB
Go
package lexpr
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import (
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"context"
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"strings"
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)
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type Lexpr struct {
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operators map[string]Operator
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functions map[string]func(ts *TokenStack) error
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variables map[string]any
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}
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func New(opts ...Opt) *Lexpr {
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l := &Lexpr{}
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for _, o := range opts {
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o(l)
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}
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return l
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}
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func (l *Lexpr) Eval(ctx context.Context, expression string) chan Result {
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lexer := newLex()
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lexems := lexer.parse(ctx, expression)
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tokens := l.tokenize(ctx, lexems)
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rpnTokens := infixToRpn(ctx, tokens)
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return l.execute(ctx, rpnTokens)
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}
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func (l *Lexpr) SetFunction(name string, fn func(ts *TokenStack) error) *Lexpr {
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l.functions[strings.ToLower(name)] = fn
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return l
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}
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func (l *Lexpr) SetOperator(name string, fn func(ts *TokenStack) error, priority int, leftAssoc bool) *Lexpr {
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l.operators[strings.ToLower(name)] = Operator{
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handler: fn,
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priority: priority,
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leftAssoc: leftAssoc,
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}
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return l
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}
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func (l *Lexpr) SetVariable(name string, value any) *Lexpr {
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l.variables[strings.ToLower(name)] = value
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return l
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}
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type Result struct {
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Value any
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Error error
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}
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