diff --git a/ASTPlayground/UserLib.json b/ASTPlayground/UserLib.json
index 400bf42..eeba53d 100644
--- a/ASTPlayground/UserLib.json
+++ b/ASTPlayground/UserLib.json
@@ -541,5 +541,706 @@
                 }
             ]
         }
+    },
+    "linear-regression": {
+        "NodeType": "LambdaExpr",
+        "Parameters": [
+            {
+                "NodeType": "Identifier",
+                "Name": "x-series"
+            },
+            {
+                "NodeType": "Identifier",
+                "Name": "y-series"
+            }
+        ],
+        "Body": {
+            "NodeType": "Block",
+            "Expressions": [
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "series-count"
+                    },
+                    "Initializer": {
+                        "NodeType": "LambdaExpr",
+                        "Parameters": [
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "series"
+                            }
+                        ],
+                        "Body": {
+                            "NodeType": "FunctionCall",
+                            "Callee": {
+                                "NodeType": "Identifier",
+                                "Name": "Reduce"
+                            },
+                            "Arguments": [
+                                {
+                                    "NodeType": "Identifier",
+                                    "Name": "series"
+                                },
+                                {
+                                    "NodeType": "Constant",
+                                    "Value": {
+                                        "Kind": "Scalar",
+                                        "Value": {
+                                            "Kind": "Ordinal",
+                                            "Value": 0
+                                        }
+                                    }
+                                },
+                                {
+                                    "NodeType": "LambdaExpr",
+                                    "Parameters": [
+                                        {
+                                            "NodeType": "Identifier",
+                                            "Name": "acc"
+                                        },
+                                        {
+                                            "NodeType": "Identifier",
+                                            "Name": "item"
+                                        }
+                                    ],
+                                    "Body": {
+                                        "NodeType": "FunctionCall",
+                                        "Callee": {
+                                            "NodeType": "Identifier",
+                                            "Name": "+"
+                                        },
+                                        "Arguments": [
+                                            {
+                                                "NodeType": "Identifier",
+                                                "Name": "acc"
+                                            },
+                                            {
+                                                "NodeType": "Constant",
+                                                "Value": {
+                                                    "Kind": "Scalar",
+                                                    "Value": {
+                                                        "Kind": "Ordinal",
+                                                        "Value": 1
+                                                    }
+                                                }
+                                            }
+                                        ]
+                                    }
+                                }
+                            ]
+                        }
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "sum-product"
+                    },
+                    "Initializer": {
+                        "NodeType": "LambdaExpr",
+                        "Parameters": [
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "xs"
+                            },
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "ys"
+                            }
+                        ],
+                        "Body": {
+                            "NodeType": "Block",
+                            "Expressions": [
+                                {
+                                    "NodeType": "VarDecl",
+                                    "Identifier": {
+                                        "NodeType": "Identifier",
+                                        "Name": "loop"
+                                    },
+                                    "Initializer": {
+                                        "NodeType": "LambdaExpr",
+                                        "Parameters": [
+                                            {
+                                                "NodeType": "Identifier",
+                                                "Name": "i"
+                                            },
+                                            {
+                                                "NodeType": "Identifier",
+                                                "Name": "acc"
+                                            }
+                                        ],
+                                        "Body": {
+                                            "NodeType": "IfExpr",
+                                            "Condition": {
+                                                "NodeType": "FunctionCall",
+                                                "Callee": {
+                                                    "NodeType": "Identifier",
+                                                    "Name": "="
+                                                },
+                                                "Arguments": [
+                                                    {
+                                                        "NodeType": "Identifier",
+                                                        "Name": "i"
+                                                    },
+                                                    {
+                                                        "NodeType": "FunctionCall",
+                                                        "Callee": {
+                                                            "NodeType": "Identifier",
+                                                            "Name": "series-count"
+                                                        },
+                                                        "Arguments": [
+                                                            {
+                                                                "NodeType": "Identifier",
+                                                                "Name": "xs"
+                                                            }
+                                                        ]
+                                                    }
+                                                ]
+                                            },
+                                            "ThenBranch": {
+                                                "NodeType": "Identifier",
+                                                "Name": "acc"
+                                            },
+                                            "ElseBranch": {
+                                                "NodeType": "Recur",
+                                                "Arguments": [
+                                                    {
+                                                        "NodeType": "FunctionCall",
+                                                        "Callee": {
+                                                            "NodeType": "Identifier",
+                                                            "Name": "+"
+                                                        },
+                                                        "Arguments": [
+                                                            {
+                                                                "NodeType": "Identifier",
+                                                                "Name": "i"
+                                                            },
+                                                            {
+                                                                "NodeType": "Constant",
+                                                                "Value": {
+                                                                    "Kind": "Scalar",
+                                                                    "Value": {
+                                                                        "Kind": "Ordinal",
+                                                                        "Value": 1
+                                                                    }
+                                                                }
+                                                            }
+                                                        ]
+                                                    },
+                                                    {
+                                                        "NodeType": "FunctionCall",
+                                                        "Callee": {
+                                                            "NodeType": "Identifier",
+                                                            "Name": "+"
+                                                        },
+                                                        "Arguments": [
+                                                            {
+                                                                "NodeType": "Identifier",
+                                                                "Name": "acc"
+                                                            },
+                                                            {
+                                                                "NodeType": "FunctionCall",
+                                                                "Callee": {
+                                                                    "NodeType": "Identifier",
+                                                                    "Name": "*"
+                                                                },
+                                                                "Arguments": [
+                                                                    {
+                                                                        "NodeType": "Indexer",
+                                                                        "Base": {
+                                                                            "NodeType": "Identifier",
+                                                                            "Name": "xs"
+                                                                        },
+                                                                        "Index": {
+                                                                            "NodeType": "Identifier",
+                                                                            "Name": "i"
+                                                                        }
+                                                                    },
+                                                                    {
+                                                                        "NodeType": "Indexer",
+                                                                        "Base": {
+                                                                            "NodeType": "Identifier",
+                                                                            "Name": "ys"
+                                                                        },
+                                                                        "Index": {
+                                                                            "NodeType": "Identifier",
+                                                                            "Name": "i"
+                                                                        }
+                                                                    }
+                                                                ]
+                                                            }
+                                                        ]
+                                                    }
+                                                ]
+                                            }
+                                        }
+                                    }
+                                },
+                                {
+                                    "NodeType": "FunctionCall",
+                                    "Callee": {
+                                        "NodeType": "Identifier",
+                                        "Name": "loop"
+                                    },
+                                    "Arguments": [
+                                        {
+                                            "NodeType": "Constant",
+                                            "Value": {
+                                                "Kind": "Scalar",
+                                                "Value": {
+                                                    "Kind": "Ordinal",
+                                                    "Value": 0
+                                                }
+                                            }
+                                        },
+                                        {
+                                            "NodeType": "Constant",
+                                            "Value": {
+                                                "Kind": "Scalar",
+                                                "Value": {
+                                                    "Kind": "Ordinal",
+                                                    "Value": 0
+                                                }
+                                            }
+                                        }
+                                    ]
+                                }
+                            ]
+                        }
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "n"
+                    },
+                    "Initializer": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "series-count"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "x-series"
+                            }
+                        ]
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "sum-x"
+                    },
+                    "Initializer": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "Reduce"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "x-series"
+                            },
+                            {
+                                "NodeType": "Constant",
+                                "Value": {
+                                    "Kind": "Scalar",
+                                    "Value": {
+                                        "Kind": "Ordinal",
+                                        "Value": 0
+                                    }
+                                }
+                            },
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "+"
+                            }
+                        ]
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "sum-y"
+                    },
+                    "Initializer": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "Reduce"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "y-series"
+                            },
+                            {
+                                "NodeType": "Constant",
+                                "Value": {
+                                    "Kind": "Scalar",
+                                    "Value": {
+                                        "Kind": "Ordinal",
+                                        "Value": 0
+                                    }
+                                }
+                            },
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "+"
+                            }
+                        ]
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "sum-x-sq"
+                    },
+                    "Initializer": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "Reduce"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "FunctionCall",
+                                "Callee": {
+                                    "NodeType": "Identifier",
+                                    "Name": "Map"
+                                },
+                                "Arguments": [
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "x-series"
+                                    },
+                                    {
+                                        "NodeType": "LambdaExpr",
+                                        "Parameters": [
+                                            {
+                                                "NodeType": "Identifier",
+                                                "Name": "x"
+                                            }
+                                        ],
+                                        "Body": {
+                                            "NodeType": "FunctionCall",
+                                            "Callee": {
+                                                "NodeType": "Identifier",
+                                                "Name": "*"
+                                            },
+                                            "Arguments": [
+                                                {
+                                                    "NodeType": "Identifier",
+                                                    "Name": "x"
+                                                },
+                                                {
+                                                    "NodeType": "Identifier",
+                                                    "Name": "x"
+                                                }
+                                            ]
+                                        }
+                                    }
+                                ]
+                            },
+                            {
+                                "NodeType": "Constant",
+                                "Value": {
+                                    "Kind": "Scalar",
+                                    "Value": {
+                                        "Kind": "Ordinal",
+                                        "Value": 0
+                                    }
+                                }
+                            },
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "+"
+                            }
+                        ]
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "sum-xy"
+                    },
+                    "Initializer": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "sum-product"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "x-series"
+                            },
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "y-series"
+                            }
+                        ]
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "m-numerator"
+                    },
+                    "Initializer": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "-"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "FunctionCall",
+                                "Callee": {
+                                    "NodeType": "Identifier",
+                                    "Name": "*"
+                                },
+                                "Arguments": [
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "n"
+                                    },
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "sum-xy"
+                                    }
+                                ]
+                            },
+                            {
+                                "NodeType": "FunctionCall",
+                                "Callee": {
+                                    "NodeType": "Identifier",
+                                    "Name": "*"
+                                },
+                                "Arguments": [
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "sum-x"
+                                    },
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "sum-y"
+                                    }
+                                ]
+                            }
+                        ]
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "m-denominator"
+                    },
+                    "Initializer": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "-"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "FunctionCall",
+                                "Callee": {
+                                    "NodeType": "Identifier",
+                                    "Name": "*"
+                                },
+                                "Arguments": [
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "n"
+                                    },
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "sum-x-sq"
+                                    }
+                                ]
+                            },
+                            {
+                                "NodeType": "FunctionCall",
+                                "Callee": {
+                                    "NodeType": "Identifier",
+                                    "Name": "*"
+                                },
+                                "Arguments": [
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "sum-x"
+                                    },
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "sum-x"
+                                    }
+                                ]
+                            }
+                        ]
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "m"
+                    },
+                    "Initializer": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "/"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "m-numerator"
+                            },
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "m-denominator"
+                            }
+                        ]
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "mean-x"
+                    },
+                    "Initializer": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "/"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "sum-x"
+                            },
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "n"
+                            }
+                        ]
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "mean-y"
+                    },
+                    "Initializer": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "/"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "sum-y"
+                            },
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "n"
+                            }
+                        ]
+                    }
+                },
+                {
+                    "NodeType": "VarDecl",
+                    "Identifier": {
+                        "NodeType": "Identifier",
+                        "Name": "b"
+                    },
+                    "Initializer": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "-"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "mean-y"
+                            },
+                            {
+                                "NodeType": "FunctionCall",
+                                "Callee": {
+                                    "NodeType": "Identifier",
+                                    "Name": "*"
+                                },
+                                "Arguments": [
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "m"
+                                    },
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "mean-x"
+                                    }
+                                ]
+                            }
+                        ]
+                    }
+                },
+                {
+                    "NodeType": "LambdaExpr",
+                    "Parameters": [
+                        {
+                            "NodeType": "Identifier",
+                            "Name": "x"
+                        }
+                    ],
+                    "Body": {
+                        "NodeType": "FunctionCall",
+                        "Callee": {
+                            "NodeType": "Identifier",
+                            "Name": "+"
+                        },
+                        "Arguments": [
+                            {
+                                "NodeType": "FunctionCall",
+                                "Callee": {
+                                    "NodeType": "Identifier",
+                                    "Name": "*"
+                                },
+                                "Arguments": [
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "m"
+                                    },
+                                    {
+                                        "NodeType": "Identifier",
+                                        "Name": "x"
+                                    }
+                                ]
+                            },
+                            {
+                                "NodeType": "Identifier",
+                                "Name": "b"
+                            }
+                        ]
+                    }
+                }
+            ]
+        }
     }
 }
\ No newline at end of file