add m_replace

src/experimental/note.md

@@ -23,6 +23,8 @@ new:
 
 - sorted, contains
 
+- m_replace?
+
 deprecated:
     rails2sections: use m_transpose
     has

src/matrix/m_replace.scad

@@ -0,0 +1,16 @@
+function m_replace(m, x, y, value) =
+    let(
+		rowY = m[y],
+        leng_rowY = len(rowY),
+		newRowY = [
+			each [for(i = 0; i < x; i = i + 1) rowY[i]],
+			value,
+			each [for(i = x + 1; i < leng_rowY; i = i + 1) rowY[i]]
+		],
+        row_leng = len(m)
+	)
+    [
+        each [for(i = 0; i < y; i = i + 1) m[i]],
+        newRowY,
+        each [for(i = y + 1; i < row_leng; i = i + 1) m[i]]
+    ];