From bf2fe06e463e0fb21bda7cb0e341dcc3636a1bfe Mon Sep 17 00:00:00 2001
From: eitsupi <ts1s1andn@gmail.com>
Date: Sun, 31 Mar 2024 04:10:04 +0000
Subject: [PATCH] WIP feat: new generic function `as_polars_expr()` [skip ci]

---
 R/as_polars_expr.R | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 R/as_polars_expr.R

diff --git a/R/as_polars_expr.R b/R/as_polars_expr.R
new file mode 100644
index 000000000..d54f11cc7
--- /dev/null
+++ b/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