added type casts

stdlib/arith.go

@@ -29,6 +29,27 @@ import (
 // perhaps we simply write out arithmetic routines that operate on the strings
 // then we need not worry about storage length.
 
+func num_cast(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
+    in = in.Eval(f, a, false)
+    if in.Tag != ast.STRING {
+        log.Log(log.ERR,
+            "only a string can successfully be cast to a number",
+            "number_cast")
+        return nil
+    }
+
+    if !ast.StrIsNumber(in.Value()) {
+        log.Log(log.ERR,
+            "string failed number cast",
+            "number_cast")
+        return nil
+    }
+
+    out := in.Copy()
+    out.Tag = ast.NUMBER
+    return out
+}
+
 func add(in *ast.Token, a ast.VarTable, f ast.FuncTable) *ast.Token {
     var res float64
 

stdlib/bool.go

@@ -23,6 +23,28 @@ import (
     "gitlab.com/whom/shs/ast"
 )
 
+func bool_cast(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
+    in = in.Eval(ft, vt, false)
+    if in.Tag == ast.LIST || in.Tag == ast.NUMBER {
+        log.Log(log.ERR,
+            "only strings successfully cast to bool",
+            "bool cast")
+        return nil
+    }
+
+    body := in.Value()
+    if body != ast.TRUE && body != ast.FALSE {
+        log.Log(log.ERR,
+            "cast to bool failed",
+            "bool cast")
+        return nil
+    }
+
+    res := &ast.Token{ Tag: ast.BOOL }
+    res.Set(body)
+    return res
+}
+
 func not(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
     in = in.Eval(ft, vt, false)
 

stdlib/stdlib.go

@@ -77,6 +77,27 @@ func GenFuncTable() ast.FuncTable {
             Args:           1,
         },
 
+        "bool": &ast.Function{
+            Function: bool_cast,
+            Name:        "bool",
+            TimesCalled:      0,
+            Args:             1,
+        },
+
+        "string": &ast.Function{
+            Function: str_cast,
+            Name:     "string",
+            TimesCalled:     0,
+            Args:            1,
+        },
+
+        "number": &ast.Function{
+            Function: num_cast,
+            Name:     "number",
+            TimesCalled:     0,
+            Args:            1,
+        },
+
        "...": &ast.Function{
             Function: expand,
             Name:      "...",

stdlib/string.go

@@ -43,6 +43,13 @@ func concat(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
     return t
 }
 
+func str_cast(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
+    body := in.Eval(ft, vt, false).String()
+    res := &ast.Token{ Tag: ast.STRING }
+    res.Set(body)
+    return res
+}
+
 func print_str(in *ast.Token, vt ast.VarTable, ft ast.FuncTable) *ast.Token {
     body := in.Eval(ft, vt, false).String()
     if body[0] != body[len(body)-1] && body[0] != '"' {