add list functions to stdlib

stdlib/Readme.md

@@ -13,7 +13,7 @@ type Function struct {
     function    Operation
     name        string
     timesCalled int
-    args        int // TODO: Make this a list of expected types (TAGs)
+    args        int
 }
 
 type FuncTable map[string]*Function
@@ -31,6 +31,12 @@ The standard library is loaded during the init step of the repl (or interpreter
 2. *Create a `Function` to encapsulate your `Operation`.* Make sure to set the `args` and `name` fields. Args will be used to validate function calls and Name will be used in debug/log output.
 3. *Add your `Function` to the `FuncTable`.* Make sure your `Operations`s get added to the table generated in `GenFuncTable`.
 
+## Tips
+- You can use the Log module to add helpful output to your functions.
+- Try not to clutter the output with unnessesary ERR level logging.
+- Make sure you properly set the Next element of any Token you swap into a list
+- Make sure you properly set the Next element of the previous Token as you swap a token into a list
+
 ## License
 Copyright (C) 2019 Aidan Hahn.
 

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
+}

stdlib/stdlib.go

@@ -23,6 +23,67 @@ import (
 )
 
 func GenFuncTable() ast.FuncTable {
-    var stdlib FuncTable
+    var stdlib = ast.FuncTable{
+        "...": &ast.Function{
+            Function: expand,
+            Name:      "...",
+            TimesCalled:   0,
+            Args:          1,
+        },
+
+        "append": &ast.Function{
+            Function: l_append,
+            Name:     "append",
+            TimesCalled:     0,
+            Args:           -1,
+        },
+    }
+
     return stdlib
 }
+
+// TODO: put list funcs in their own file
+
+/* 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
+}