Substitute instead of mask

NAMESPACE

@@ -1,9 +1,16 @@
 # Generated by roxygen2: do not edit by hand
 
 S3method("[[<-",tensorflow.python.ops.tensor_array_ops.TensorArray)
+export(ag_break)
+export(ag_for)
+export(ag_if)
 export(ag_if_vars)
 export(ag_loop_vars)
 export(ag_name)
+export(ag_next)
+export(ag_on.exit)
+export(ag_stopifnot)
+export(ag_while)
 export(ag_while_opts)
 export(autograph)
 export(tf_assert)

NEWS.md

@@ -1,5 +1,15 @@
 # tfautograph (development version)
 
+* `ag_if()` and related autographing control-flow functions are now exported,
+  allowing for precise control of which expressions produce graph nodes.
+
+* `autograph()` now works by substituting symbols in language objects rather than
+  masking them by splicing in an environment. This will make it easier to discover
+  what `autograph()` is doing in interactive contexts.
+
+* `autograph()` now returns functions and language objects like expressions,
+  calls, and formulas, with an S3 class attribute "tfautographed".
+
 * `for` in an eager `autograph()` context gains the ability to process
   arbitrary python iterables, including `tf.distribute.DistributedDataset`.
 

R/break-next.R

@@ -24,7 +24,7 @@ uncaught_loop_control_flow_condition <-
   }
 
 
-
+#' @export
 ag_break <- function() {
   env <- parent.frame()
   tryCatch(
@@ -37,6 +37,7 @@ ag_break <- function() {
   )
 }
 
+#' @export
 ag_next <- function() {
   env <- parent.frame()
   tryCatch(

R/ctrl-deps.R

@@ -1,5 +1,5 @@
 
-
+#' @export
 ag_on.exit <- function(expr = NULL, add = TRUE, after = FALSE) {
 
   env <- parent.frame()

R/for.R

@@ -1,5 +1,5 @@
 
-
+#' @export
 ag_for <- function(var, iterable, body) {
   var  <- substitute(var)
   body <- substitute(body)

R/if.R

@@ -1,6 +1,6 @@
 
 
-
+#' @export
 #' @importFrom reticulate dict
 ag_if <- function(cond, true, false = NULL) {
   true <- substitute(true)

R/stopifnot.R

@@ -1,4 +1,5 @@
 
+#' @export
 ag_stopifnot <- function(..., exprs, local = TRUE) {
   if(missing(exprs)) {
     dots <- eval(substitute(alist(...)))

R/while.R

@@ -1,5 +1,5 @@
 
-
+#' @export
 ag_while <- function(cond, body) {
   cond <- substitute(cond)
   body <- substitute(body)

R/zzz-autograph.R

@@ -13,6 +13,16 @@ ag_mask_list <- list(
 )
 
 
+ag_mask_subtitution_list <- alist(
+  `if` = tfautograph::ag_if,
+  `for` = tfautograph::ag_for,
+  `while` = tfautograph::ag_while,
+  `break` = tfautograph::ag_break,
+  `next` = tfautograph::ag_next,
+  `stopifnot` = tfautograph::ag_stopifnot,
+  `on.exit` = tfautograph::ag_on.exit
+)
+
 
 
 #' Autograph R code
@@ -40,16 +50,36 @@ autograph <- function(x) {
   xe <- substitute(x)
   env <- parent.frame()
 
+
   if (is.symbol(xe)) {
-    # function, formula, or something with `environment<-` method
-    environment(x) <- new_ag_mask(parent = environment(x))
+    # function, language, or something with `environment<-` method
+
+    if (inherits(xe, "python.builtin.object"))
+      stop("Only R objects can be autographed")
+
+    if (is.function(x))
+      body(x) <- eval(call("substitute", body(x), ag_mask_subtitution_list))
+    else if (is.language(x)) # formula, expression(), or call() (probably to `{`)
+      x <- eval(call("substitute", x, ag_mask_subtitution_list))
+    else
+      environment(x) <- new_ag_mask(parent = environment(x))
+
+    class(x) <- unique(c("tfautographed", class(x)))
     return(x)
   }
 
   # in line expression
-  fn <- as_outcome_fn(xe, new_ag_mask(parent = env))
+  # fn <- as_outcome_fn(xe, new_ag_mask(parent = env))
+
+  xe <- eval(call("substitute", xe, ag_mask_subtitution_list))
+  fn <- as_outcome_fn(xe, env)
   outcome <- fn()
 
+  outcome <- rapply(list(outcome), function(x) {
+    class(x) <- unique(c("tfautographed", class(x)))
+    x
+  }, how = "replace", classes = c("function", "language"))[[1L]]
+
   export_modified(outcome$modified, env)
 
   if(isFALSE(outcome$visible) ||
@@ -60,6 +90,7 @@ autograph <- function(x) {
 }
 
 
+
 new_ag_mask <- function(parent = parent.frame()) {
 
   ag_mask <- list2env(ag_mask_list, parent = parent)