83 lines
2.2 KiB
Go
83 lines
2.2 KiB
Go
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/* SHS: Syntactically Homogeneous Shell
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* Copyright (C) 2019 Aidan Hahn
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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package stdlib
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import "gitlab.com/whom/shs/ast"
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/* return one evaluated form or another based on the boolean statement
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*/
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func shs_if(in *ast.Token, vt VarTable, ft FuncTable) *ast.Token {
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cond := in
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t := cond.Next
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f := t.Next
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cond.Next = nil
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t.Next = nil
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cond = cond.Eval(ft, vt, false)
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if cond == nil || cond.Tag != ast.BOOL {
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log.Log(log.ERR,
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"first argument to if must be a bool statement",
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"if")
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return nil
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}
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switch cond.Value() {
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case ast.TRUE:
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return t
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case ast.FALSE:
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return f
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default:
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log.Log(log.ERR,
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"improper bool!",
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"if")
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return nil
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}
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}
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/* continually eval n forms while element #1 evals to T
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*/
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func shs_while(in *ast.Token, vt VarTable, ft FuncTable) *ast.Token {
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cond := in
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forms := in.Next
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in.Next = nil
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var res *ast.Token
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eval := cond.Eval(ft, vt, false)
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if cond == nil || cond.Tag != ast.BOOL {
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log.Log(log.ERR,
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"first argument to while must be a bool statement",
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"while")
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return nil
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}
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// slight downside here: doesnt log when the wrong tag is set
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for eval.Tag == ast.BOOL && eval.Value() == 'T' {
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// eval all forms
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for i := forms; i != nil; i = i.Next {
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res = i.Eval(ft, vt, false)
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}
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// retest eval
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eval := cond.Eval(ft, vt, false)
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}
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return res
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}
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