add list functions to stdlib

stdlib/list.go

@@ -0,0 +1,67 @@
+/*   SHS: Syntactically Homogeneous Shell
+ *   Copyright (C) 2019  Aidan Hahn
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package stdlib
+
+import (
+    "git.callpipe.com/aidan/shs/ast"
+    "git.callpipe.com/aidan/shs/log"
+)
+
+/* EXPAND
+ * Takes 1 element: a list
+ * retuns a sequence of elements (list contents)
+ * in event a not-list is passed in, returns the arg.
+ */
+func expand(input *ast.Token, vars ast.VarTable, funcs ast.FuncTable) *ast.Token {
+    if input.Tag != ast.LIST {
+        log.Log(log.DEBUG, "expand called on not a list", "expand")
+        return input
+    }
+
+    return input.Inner.(*ast.Token)
+}
+
+/* L_APPEND (append from repl)
+ * Appends N elements to the end of a list
+ * Arg one is a list, next args are appended
+ * if no args are a list, a list is made from all args
+ */
+func l_append(input *ast.Token, vars ast.VarTable, funcs ast.FuncTable) *ast.Token {
+    src := input
+
+    if input.Tag != ast.LIST {
+        // TODO: Position, if I can figure out what to do with it
+        src = &ast.Token{Tag: ast.LIST, Inner: input}
+        return src
+    }
+
+    // deref inner first
+    i := src.Inner.(*ast.Token)
+    iter := &i
+    if *iter == nil {
+        src.Inner = input.Next
+        return src
+    }
+
+    for (*iter).Next != nil {
+        iter = &((*iter).Next)
+    }
+    (*iter).Next = input.Next
+
+    return src
+}