WIP feat: new generic function as_polars_expr() [skip ci]

R/as_polars_expr.R

@@ -0,0 +1,31 @@
+#' Similar to `parse_as_expression` in Python Polars.
+as_polars_expr = function(x, ...) {
+  UseMethod("as_polars_expr")
+}
+
+
+as_polars_expr.default(x, ...) = function(x, ...) {
+  pl$lit(x)
+}
+
+
+as_polars_expr.RPolarsExpr = function(x, ...) {
+  x
+}
+
+
+as_polars_expr.character = function(x, ..., as_lit = FALSE) {
+  if (as_lit) {
+    pl$lit(x)
+  } else {
+    pl$col(x)
+  }
+}
+
+
+as_polars_expr.RPolarsThen = function(x, ...) {
+  x$otherwise(NULL)
+}
+
+
+as_polars_expr.RPolarsChainedThen = as_polars_expr.RPolarsThen