Merge pull request #1423 from dfalbel/jupyter-compat-fix

R/knitr-engine.R

@@ -196,22 +196,26 @@ eng_python <- function(options) {
     # clear the last value object (so we can tell if it was updated)
     py_compile_eval("'__reticulate_placeholder__'")
 
+    # use trailing semicolon to suppress output of return value
+    suppress <- grepl(";\\s*$", snippet) || (jupyter_compat & !last_range)
+    compile_mode <- if (suppress) "exec" else "single"
+
     # run code and capture output
-    captured <- if (capture_errors)
-      tryCatch(py_compile_eval(snippet, 'single'), error = identity)
+    captured_stdout <- if (capture_errors)
+      tryCatch(py_compile_eval(snippet, compile_mode), error = identity)
     else
-      py_compile_eval(snippet, 'single')
+      py_compile_eval(snippet, compile_mode)
 
     # handle matplotlib plots and other special output
     captured <- eng_python_autoprint(
-      captured = captured,
+      captured = captured_stdout,
       options  = options
     )
 
     # A trailing ';' suppresses output.
     # In jupyter mode, only the last expression in a chunk has repr() output.
-    if (grepl(";\\s*$", snippet) | (jupyter_compat & !last_range))
-      captured <- ""
+    if (suppress)
+      captured <- captured_stdout
 
     # emit outputs if we have any
     has_outputs <-

tests/testthat/_snaps/python-knitr-engine/knitr-print.md

@@ -2,3 +2,84 @@
     bt$print("Hello world")
 
     ## Hello world
+
+## Print statements should always be captured
+
+In `jupyter_compat = FALSE`: we should only see the output of both
+expressions.
+
+    print(1)
+
+    ## 1
+
+    print(2)
+
+    ## 2
+
+In `jupyter_compat = TRUE`: we should only see the output of both
+expressions.
+
+    print(1)
+
+    ## 1
+
+    print(2)
+
+    ## 2
+
+## Only outputs of last expressions are captured in jupyter compat
+
+In `jupyter_compat = FALSE`: we should only see the output of both
+expressions.
+
+    1 + 0
+
+    ## 1
+
+    1 + 1
+
+    ## 2
+
+`jupyter_compat = TRUE`: we should only see the output of the last
+expression.
+
+    1 + 0
+    1 + 1
+
+    ## 2
+
+## One can disable outputs by using `;`
+
+In `jupyter_compat = FALSE`: we should only see the print statement
+output
+
+    print("hello");
+
+    ## hello
+
+    1 + 0;
+    1 + 1;
+
+`jupyter_compat = TRUE`: we should only see the print statement output
+
+    print("hello");
+
+    ## hello
+
+    1 + 0;
+    1 + 1;
+
+## `jupyter_compat` works with interleaved expressions
+
+    print('first_stdout')
+
+    ## first_stdout
+
+    'first_expression'
+    print('second_stdout')
+
+    ## second_stdout
+
+    'final_expression'
+
+    ## 'final_expression'

tests/testthat/_snaps/python-knitr-engine/knitr-print2.md

@@ -2,3 +2,84 @@
     bt$print("Hello world")
 
     ## Hello world
+
+## Print statements should always be captured
+
+In `jupyter_compat = FALSE`: we should only see the output of both
+expressions.
+
+    print(1)
+
+    ## 1
+
+    print(2)
+
+    ## 2
+
+In `jupyter_compat = TRUE`: we should only see the output of both
+expressions.
+
+    print(1)
+
+    ## 1
+
+    print(2)
+
+    ## 2
+
+## Only outputs of last expressions are captured in jupyter compat
+
+In `jupyter_compat = FALSE`: we should only see the output of both
+expressions.
+
+    1 + 0
+
+    ## 1
+
+    1 + 1
+
+    ## 2
+
+`jupyter_compat = TRUE`: we should only see the output of the last
+expression.
+
+    1 + 0
+    1 + 1
+
+    ## 2
+
+## One can disable outputs by using `;`
+
+In `jupyter_compat = FALSE`: we should only see the print statement
+output
+
+    print("hello");
+
+    ## hello
+
+    1 + 0;
+    1 + 1;
+
+`jupyter_compat = TRUE`: we should only see the print statement output
+
+    print("hello");
+
+    ## hello
+
+    1 + 0;
+    1 + 1;
+
+## `jupyter_compat` works with interleaved expressions
+
+    print('first_stdout')
+
+    ## first_stdout
+
+    'first_expression'
+    print('second_stdout')
+
+    ## second_stdout
+
+    'final_expression'
+
+    ## 'final_expression'

tests/testthat/resources/knitr-print.Rmd

@@ -8,3 +8,63 @@ bt <- reticulate::import_builtins()
 bt$print("Hello world")
 ```
 
+## Print statements should always be captured
+
+In `jupyter_compat = FALSE`: we should only see the output of both expressions.
+
+```{python}
+print(1)
+print(2)
+```
+
+In `jupyter_compat = TRUE`: we should only see the output of both expressions.
+
+```{python, jupyter_compat = TRUE}
+print(1)
+print(2)
+```
+
+## Only outputs of last expressions are captured in jupyter compat
+
+In `jupyter_compat = FALSE`: we should only see the output of both expressions.
+
+```{python}
+1 + 0
+1 + 1
+```
+
+`jupyter_compat = TRUE`: we should only see the output of the last expression.
+
+```{python, jupyter_compat = TRUE}
+1 + 0
+1 + 1
+```
+
+## One can disable outputs by using `;`
+
+In `jupyter_compat = FALSE`: we should only see the print statement output
+
+```{python}
+print("hello");
+1 + 0;
+1 + 1;
+```
+
+`jupyter_compat = TRUE`: we should only see the print statement output
+
+```{python, jupyter_compat = TRUE}
+print("hello");
+1 + 0;
+1 + 1;
+```
+
+## `jupyter_compat` works with interleaved expressions
+
+```{python, jupyter_compat=TRUE}
+print('first_stdout')
+'first_expression'
+print('second_stdout')
+'final_expression'
+```
+
+