Add R backend-controlled format options to data explorer

.github/workflows/cla.yml

@@ -49,7 +49,7 @@ jobs:
             before we accept your contribution. You can sign the CLA by posting
             a comment on this PR saying:
 
-          allowlist: DavisVaughan, dependabot[bot], dfalbel, isabelizimm, jonvanausdeln, lionel-, nstrayer, petetronic, positron-bot[bot], seeM, sharon-wang, softwarenerd, timtmok, wesm, copilot[bot], copilot-swe-agent[bot], Copilot
+          allowlist: DavisVaughan, dependabot[bot], dfalbel, isabelizimm, jonvanausdeln, lionel-, nstrayer, petetronic, positron-bot[bot], seeM, sharon-wang, softwarenerd, timtmok, wesm, Copilot
 
           # the followings are the optional inputs - If the optional inputs are not given, then default values will be taken
           #remote-organization-name: enter the remote organization name where the signatures should be stored (Default is storing the signatures in the same repository)

crates/amalthea/src/comm/data_explorer_comm.rs

@@ -1,7 +1,7 @@
 // @generated
 
 /*---------------------------------------------------------------------------------------------
- *  Copyright (C) 2024-2025 Posit Software, PBC. All rights reserved.
+ *  Copyright (C) 2024-2026 Posit Software, PBC. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
 //
@@ -60,6 +60,13 @@ pub struct FilterResult {
 	pub had_errors: Option<bool>
 }
 
+/// Result of setting import options
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+pub struct SetDatasetImportOptionsResult {
+	/// An error message if setting the options failed
+	pub error_message: Option<String>
+}
+
 /// The current backend state for the data explorer
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
 pub struct BackendState {
@@ -94,7 +101,11 @@ pub struct BackendState {
 
 	/// Optional experimental parameter to provide an explanation when
 	/// connected=false. This parameter may change.
-	pub error_message: Option<String>
+	pub error_message: Option<String>,
+
+	/// Optional formatting options provided by the backend for displaying
+	/// data values
+	pub format_options: Option<FormatOptions>
 }
 
 /// Schema for a column in a table
@@ -703,6 +714,15 @@ pub struct ColumnSelection {
 	pub spec: ArraySelection
 }
 
+/// Import options for file-based data sources. Currently supports options
+/// for delimited text files (CSV, TSV).
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+pub struct DatasetImportOptions {
+	/// Whether the first row contains column headers (for delimited text
+	/// files)
+	pub has_header_row: Option<bool>
+}
+
 /// Possible values for SortOrder in SearchSchema
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq, strum_macros::Display, strum_macros::EnumString)]
 pub enum SearchSchemaSortOrder {
@@ -1193,6 +1213,13 @@ pub struct GetColumnProfilesParams {
 	pub format_options: FormatOptions,
 }
 
+/// Parameters for the SetDatasetImportOptions method.
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
+pub struct SetDatasetImportOptionsParams {
+	/// Import options to apply
+	pub options: DatasetImportOptions,
+}
+
 /// Parameters for the ReturnColumnProfiles method.
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
 pub struct ReturnColumnProfilesParams {
@@ -1289,6 +1316,14 @@ pub enum DataExplorerBackendRequest {
 	#[serde(rename = "get_column_profiles")]
 	GetColumnProfiles(GetColumnProfilesParams),
 
+	/// Set import options for file-based data sources
+	///
+	/// Set import options for file-based data sources (like CSV files) and
+	/// reimport the data. This method is primarily used by file-based
+	/// backends like DuckDB.
+	#[serde(rename = "set_dataset_import_options")]
+	SetDatasetImportOptions(SetDatasetImportOptionsParams),
+
 	/// Get the state
 	///
 	/// Request the current backend state (table metadata, explorer state, and
@@ -1337,6 +1372,9 @@ pub enum DataExplorerBackendReply {
 	/// Reply for the get_column_profiles method (no result)
 	GetColumnProfilesReply(),
 
+	/// Result of setting import options
+	SetDatasetImportOptionsReply(SetDatasetImportOptionsResult),
+
 	/// The current backend state for the data explorer
 	GetStateReply(BackendState),
 

crates/ark/src/data_explorer/r_data_explorer.rs

@@ -72,6 +72,7 @@ use crossbeam::channel::Sender;
 use crossbeam::select;
 use harp::exec::RFunction;
 use harp::exec::RFunctionExt;
+use harp::get_option;
 use harp::object::RObject;
 use harp::r_symbol;
 use harp::table_kind;
@@ -550,6 +551,10 @@ impl RDataExplorer {
                 return Err(anyhow!("Data Explorer: Not yet supported"));
             },
 
+            DataExplorerBackendRequest::SetDatasetImportOptions(_) => {
+                return Err(anyhow!("Data Explorer: Not yet supported"));
+            },
+
             DataExplorerBackendRequest::GetRowLabels(req) => {
                 let row_labels =
                     r_task(|| self.r_get_row_labels(req.selection, &req.format_options))?;
@@ -1159,6 +1164,7 @@ impl RDataExplorer {
                     }]),
                 },
             },
+            format_options: Some(Self::current_format_options()),
         };
         Ok(DataExplorerBackendReply::GetStateReply(state))
     }
@@ -1299,6 +1305,36 @@ impl RDataExplorer {
         // Call the conversion function with resolved sort keys
         convert_to_code::convert_to_code(params, object_name, &resolved_sort_keys)
     }
+
+    /// Returns the current format options as a `FormatOptions` object.
+    ///
+    /// These options are derived from the R options "scipen" and "digits". The
+    /// thresholds for scientific notation are calculated based on these
+    /// options. The `max_value_length` is set to 1000, and `thousands_sep`
+    /// is set to `None`.
+    fn current_format_options() -> FormatOptions {
+        // In R 4.2, Rf_GetOption1 (used by get_option) doesn't work correctly for scipen
+        // due to special handling added in later versions. We need to use the R interpreter's
+        // getOption() function instead. See: https://github.com/wch/r-source/commit/7f20c19
+        // Note: 'digits' works fine with Rf_GetOption1, so we don't need to change it.
+        let scipen: i64 = harp::parse_eval_global("as.integer(getOption('scipen', 0))")
+            .and_then(|obj| obj.try_into())
+            .unwrap_or(0); // R default
+        let digits: i64 = get_option("digits").try_into().unwrap_or(7); // R default
+
+        // Calculate thresholds for scientific notation
+        let max_integral_digits = (scipen + 5).max(1); // only depends on scipen
+        let large_num_digits = (digits - 5).max(0); // default to 2 d.p.
+        let small_num_digits = (scipen + 6).max(1); // only depends on scipen
+
+        FormatOptions {
+            large_num_digits,
+            small_num_digits,
+            max_integral_digits,
+            max_value_length: 1000,
+            thousands_sep: None,
+        }
+    }
 }
 
 /// Open an R object in the data viewer.

crates/ark/tests/data_explorer.rs

@@ -3108,3 +3108,63 @@ fn test_single_row_data_frame_column_profiles() {
         });
     }
 }
+
+#[test]
+fn test_format_options_state_change() {
+    let _lock = r_test_lock();
+
+    // Save the current R options so we can restore them later
+    let (original_scipen, original_digits) = r_task(|| {
+        let scipen_obj = harp::parse_eval_global("getOption('scipen')").expect("Failed to get scipen option");
+        let digits_obj = harp::parse_eval_global("getOption('digits')").expect("Failed to get digits option");
+        let scipen: i64 = scipen_obj.try_into().unwrap_or(0);
+        let digits: i64 = digits_obj.try_into().unwrap_or(7);
+        (scipen, digits)
+    });
+
+    // Set known R options for testing
+    r_task(|| {
+        harp::parse_eval_global("options(scipen = 0, digits = 7)").unwrap();
+    });
+
+    // Open a data explorer with mtcars
+    let setup = TestSetup::new("mtcars");
+    let socket = setup.socket();
+
+    // Get the initial state and verify format_options
+    TestAssertions::assert_state(&socket, |state| {
+        let format_options = state.format_options.as_ref().expect("format_options should be present");
+
+        // With scipen=0, digits=7:
+        // max_integral_digits = (0 + 5).max(1) = 5
+        // large_num_digits = (7 - 5).max(0) = 2
+        // small_num_digits = (0 + 6).max(1) = 6
+        assert_eq!(format_options.max_integral_digits, 5);
+        assert_eq!(format_options.large_num_digits, 2);
+        assert_eq!(format_options.small_num_digits, 6);
+    });
+
+    // Change R options to different values
+    r_task(|| {
+        harp::parse_eval_global("options(scipen = 10, digits = 10)").unwrap();
+    });
+
+    // Get the state again and verify format_options changed
+    TestAssertions::assert_state(&socket, |state| {
+        let format_options = state.format_options.as_ref().expect("format_options should be present");
+
+        // With scipen=10, digits=10:
+        // max_integral_digits = (10 + 5).max(1) = 15
+        // large_num_digits = (10 - 5).max(0) = 5
+        // small_num_digits = (10 + 6).max(1) = 16
+        assert_eq!(format_options.max_integral_digits, 15);
+        assert_eq!(format_options.large_num_digits, 5);
+        assert_eq!(format_options.small_num_digits, 16);
+    });
+
+    // Restore original R options
+    r_task(|| {
+        let restore_cmd = format!("options(scipen = {}, digits = {})", original_scipen, original_digits);
+        harp::parse_eval_global(&restore_cmd).expect("Failed to restore original R options");
+    });
+}