Celestino Amoroso
6ee21e10af
the previous flags allowForest and allowVarRef. Added binary operator (work in progress). Better implementation of +=,-=,*=, and /= (new) operators.
68 lines
1.4 KiB
Go
68 lines
1.4 KiB
Go
// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
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// All rights reserved.
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// operand-fraction.go
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package expr
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//https://www.youmath.it/lezioni/algebra-elementare/lezioni-di-algebra-e-aritmetica-per-scuole-medie/553-dalle-frazioni-a-numeri-decimali.html
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import (
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"errors"
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"fmt"
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)
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// -------- fraction term
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func newFractionTerm(tk *Token) *term {
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return &term{
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tk: *tk,
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parent: nil,
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children: make([]*term, 0, 2),
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position: posInfix,
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priority: priFraction,
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evalFunc: evalFraction,
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}
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}
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// -------- eval func
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func evalFraction(ctx ExprContext, opTerm *term) (v any, err error) {
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var numValue, denValue any
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var num, den int64
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var ok bool
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if numValue, denValue, err = opTerm.evalInfix(ctx); err != nil {
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return
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}
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if num, ok = numValue.(int64); !ok {
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err = fmt.Errorf("numerator must be integer, got %T (%v)", numValue, numValue)
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return
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}
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if den, ok = denValue.(int64); !ok {
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err = fmt.Errorf("denominator must be integer, got %T (%v)", denValue, denValue)
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return
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}
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if den == 0 {
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err = errors.New("division by zero")
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return
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}
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if den < 0 {
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den = -den
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num = -num
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}
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g := gcd(num, den)
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num = num / g
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den = den / g
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if den == 1 {
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v = num
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} else {
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v = &FractionType{num, den}
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}
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return
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}
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// init
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func init() {
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registerTermConstructor(SymVertBar, newFractionTerm)
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// registerTermConstructor(SymColon, newFractionTerm)
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}
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