feat: infer column type using runner (#1182)

Closes #994 

### Summary of Changes

EDA adds another execution in getting the Table placeholder to get
column types with the .getColumn().isNumeric call that based on that
evals to numeric or categorical type. In future also consider the
temporal type, but will have to overhaul the profiling and filters for
that.

packages/safe-ds-vscode/src/extension/eda/apis/runnerApi.ts

@@ -263,6 +263,12 @@ export class RunnerApi {
     private sdsStringForCorrelationHeatmap(tablePlaceholder: string, newPlaceholderName: string) {
         return 'val ' + newPlaceholderName + ' = ' + tablePlaceholder + '.plot.correlationHeatmap(); \n';
     }
+
+    private sdsStringForIsNumeric(tablePlaceholder: string, columnName: string, newPlaceholderName: string) {
+        return (
+            'val ' + newPlaceholderName + ' = ' + tablePlaceholder + '.getColumn("' + columnName + '").isNumeric; \n'
+        );
+    }
     //#endregion
 
     //#region Placeholder handling
@@ -283,6 +289,9 @@ export class RunnerApi {
                     return;
                 }
                 this.services.runtime.PythonServer.removeMessageCallback('placeholder_value', placeholderValueCallback);
+                safeDsLogger.debug(
+                    'Got placeholder value: ' + JSON.stringify(message.data.value).slice(0, 100) + '...',
+                );
                 resolve(message.data.value);
             };
 
@@ -304,8 +313,28 @@ export class RunnerApi {
     //#region Table fetching
     public async getTableByPlaceholder(tableName: string, pipelineExecutionId: string): Promise<Table | undefined> {
         safeDsLogger.debug('Getting table by placeholder: ' + tableName);
+
         const pythonTableColumns = await this.getPlaceholderValue(tableName, pipelineExecutionId);
         if (pythonTableColumns) {
+            // Get Column Types
+            safeDsLogger.debug('Getting column types for table: ' + tableName);
+            let sdsLines = '';
+            let placeholderNames: string[] = [];
+            let columnNameToPlaceholderIsNumericNameMap = new Map<string, string>();
+            for (const columnName of Object.keys(pythonTableColumns)) {
+                const newPlaceholderName = this.genPlaceholderName(columnName + '_type');
+                columnNameToPlaceholderIsNumericNameMap.set(columnName, newPlaceholderName);
+                placeholderNames.push(newPlaceholderName);
+                sdsLines += this.sdsStringForIsNumeric(tableName, columnName, newPlaceholderName);
+            }
+
+            await this.addToAndExecutePipeline(pipelineExecutionId, sdsLines, placeholderNames);
+            const columnIsNumeric = new Map<string, string>();
+            for (const [columnName, placeholderName] of columnNameToPlaceholderIsNumericNameMap) {
+                const columnType = await this.getPlaceholderValue(placeholderName, pipelineExecutionId);
+                columnIsNumeric.set(columnName, columnType as string);
+            }
+
             const table: Table = {
                 totalRows: 0,
                 name: tableName,
@@ -322,8 +351,7 @@ export class RunnerApi {
                     currentMax = columnValues.length;
                 }
 
-                const isNumerical = typeof columnValues[0] === 'number';
-                const columnType = isNumerical ? 'numerical' : 'categorical';
+                const columnType = columnIsNumeric.get(columnName) ? 'numerical' : 'categorical';
 
                 const column: Column = {
                     name: columnName,