clarify that the chunk option strip.white is for individual expressions in a code chunk (not only removing leading/trailing blank lines of a code chunk)

Author: yihui

.github/workflows/R-CMD-check.yaml

@@ -17,6 +17,7 @@ jobs:
       matrix:
         config:
           - {os: ubuntu-latest, r: 'release'}
+          - {os: ubuntu-latest, r: '4.4'}
           - {os: ubuntu-latest, r: '4.3'}
           - {os: ubuntu-latest, r: '4.2'}
           - {os: ubuntu-latest, r: '4.1'}

docs/02-fuse.Rmd

@@ -1048,8 +1048,9 @@ as is. The behavior is controlled by the option `results`, with possible values:
 
 ### `strip.white`: trim blank lines in code {#sec:option-strip-white}
 
-By default, blank lines at the beginning and end of a source code block are
-removed. To keep them, you can use the chunk option `strip.white = FALSE`.
+By default, the leading and trailing blank lines of individual code expressions
+in a code chunk are removed. To keep them, you can use the chunk option
+`strip.white = FALSE`.
 
 `{r} c(.ex(17), .ex(17, '.md'))`
 

examples/017-option-strip-white.Rmd

@@ -8,8 +8,11 @@ Keep blank lines at the beginning/end:
 
 ```{r, strip.white = FALSE}
 
-# a blank line above
+# a blank line before this expression
 1 + 1
-# and a blank line below
+
+# blank lines before and after this expression
+for (i in 1:10) {
+}
 
 ```

examples/017-option-strip-white.md

@@ -8,7 +8,7 @@ Keep blank lines at the beginning/end:
 
 ``` {.r}
 
-# a blank line above
+# a blank line before this expression
 1 + 1
 ```
 
@@ -17,6 +17,9 @@ Keep blank lines at the beginning/end:
 ```
 
 ``` {.r}
-# and a blank line below
+
+# blank lines before and after this expression
+for (i in 1:10) {
+}
 
 ```

examples/test-results-hide.Rmd

@@ -1,11 +1,17 @@
 `results = 'hide'` should try to collapse output, e.g., merge the source blocks below:
 
-```{r, results = 'hide'}
+```{r, chunk-a, results = 'hide'}
 nrow(iris)
 ncol(iris)
+
 iris
 ```
 
+Keep the blank line:
+
+```{r, chunk-a, results = 'hide', strip.white = FALSE}
+```
+
 Other types of output (such as messages) will interrupt the collapsed block:
 
 ```{r, results = 'hide'}

examples/test-results-hide.md

@@ -6,6 +6,15 @@ ncol(iris)
 iris
 ```
 
+Keep the blank line:
+
+``` {.r}
+nrow(iris)
+ncol(iris)
+
+iris
+```
+
 Other types of output (such as messages) will interrupt the collapsed block:
 
 ``` {.r}