Updated readme's, add prototype function declaration operation

stdlib/funcs.go

@@ -0,0 +1,106 @@
+/*   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 (
+    "gitlab.com/whom/shs/ast"
+    "gitlab.com/whom/shs/log"
+)
+
+func decl_func(input *ast.Token, vars ast.VarTable, funcs ast.FuncTable) *ast.Token {
+    name := input
+    if name.Tag != ast.STRING {
+        log.Log(log.ERR,
+            "non string handed to name arg",
+            "func")
+        return nil
+    }
+
+    var numArgs int
+    args := name.Next
+    if args.Tag != ast.LIST {
+        log.Log(log.ERR,
+            "argument 2 of func must be a flat list of argument symbols",
+            "func")
+        return nil
+    }
+
+    form := args.Next
+    if form.Tag != ast.LIST {
+        log.Log(log.ERR,
+            "argument 3 of func must be a form to be evaluated",
+            "func")
+        return nil
+    }
+
+    for i := args.Expand(); i != nil; i = i.Next {
+        if i.Tag != ast.SYMBOL {
+            log.Log(log.ERR,
+                "all args in user defined functions must be declared in the form of symbols",
+                "func")
+            return nil
+        }
+        numArgs += 1
+    }
+
+    ASTSYNCSTATE := ast.SyncTablesWithOSEnviron
+    inner := func(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
+        in = in.Eval(ft, vt, false)
+        if in == nil {
+            log.Log(log.ERR,
+                "error parsing arguments",
+                name.Value())
+            return nil
+        }
+
+        ast.SyncTablesWithOSEnviron = false
+        key_iter := args.Expand()
+        val_iter := in
+
+        for key_iter != nil {
+            if val_iter == nil {
+                log.Log(log.ERR,
+                    "Not enough arguments supplied",
+                    name.Value())
+            }
+
+            ast.SetVar(key_iter.Value(), val_iter, vt)
+            key_iter = key_iter.Next
+            val_iter = val_iter.Next
+        }
+
+        ast.SyncTablesWithOSEnviron = ASTSYNCSTATE
+        ret := form.Eval(ft, vt, false)
+        ast.SyncTablesWithOSEnviron = false
+        for i := args.Expand(); i != nil; i = i.Next {
+            ast.RemoveVar(i.Value(), vt)
+        }
+
+        ast.SyncTablesWithOSEnviron = ASTSYNCSTATE
+        return ret
+    }
+
+    (*funcs)[name.Value()] = &ast.Function{
+        Function:    inner,
+        Name: name.Value(),
+        TimesCalled:     0,
+        Args:      numArgs,
+    }
+    return nil
+}
+