56 lines
1.2 KiB
Go
56 lines
1.2 KiB
Go
package commands
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import (
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"fmt"
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"strings"
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"c65gm/internal/compiler"
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"c65gm/internal/preproc"
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"c65gm/internal/utils"
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)
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// ElseCommand handles ELSE statements
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// Syntax: ELSE
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// Marks alternative branch in IF...ELSE...ENDIF
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type ElseCommand struct {
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skipLabel string
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endifLabel string
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}
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func (c *ElseCommand) WillHandle(line preproc.Line) bool {
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params, err := utils.ParseParams(line.Text)
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if err != nil || len(params) == 0 {
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return false
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}
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return strings.ToUpper(params[0]) == "ELSE"
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}
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func (c *ElseCommand) Interpret(line preproc.Line, ctx *compiler.CompilerContext) error {
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params, err := utils.ParseParams(line.Text)
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if err != nil {
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return err
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}
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if len(params) != 1 {
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return fmt.Errorf("ELSE: expected 1 parameter, got %d", len(params))
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}
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// Pop skip label (where IF jumps on FALSE)
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var err2 error
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c.skipLabel, err2 = ctx.IfStack.Pop()
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if err2 != nil {
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return fmt.Errorf("ELSE: not inside IF block")
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}
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// Push new endif label (where to jump after IF block)
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c.endifLabel = ctx.IfStack.Push()
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return nil
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}
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func (c *ElseCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
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return []string{
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fmt.Sprintf("\tjmp %s", c.endifLabel),
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c.skipLabel,
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}, nil
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}
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