[CHORE] Move out datatype and schema from daft-core (#2806)

* Factors out DataType, Field, Schema into `daft-schema`
* Factors out our display logic to `common-display`
* Factors out array ffi code into `common-arrow-ffi`
* Create `StrValue` trait that allows us to pass `&dyn StrValue` to the
common-display crate without it knowing what a series is.
* Reexport `daft-schema::{DataType, Schema, Field}` for convenience 

Follow on:
* Factor out daft-scan and daft-plan dependance on daft-core. This will
allow them to directly depend on `daft-schema`

Cargo.toml

@@ -5,6 +5,7 @@ common-hashable-float-wrapper = {path = "src/common/hashable-float-wrapper", def
 common-resource-request = {path = "src/common/resource-request", default-features = false}
 common-system-info = {path = "src/common/system-info", default-features = false}
 common-tracing = {path = "src/common/tracing", default-features = false}
+common-version = {path = "src/common/version", default-features = false}
 daft-compression = {path = "src/daft-compression", default-features = false}
 daft-core = {path = "src/daft-core", default-features = false}
 daft-csv = {path = "src/daft-csv", default-features = false}

src/common/arrow-ffi/Cargo.toml

@@ -0,0 +1,11 @@
+[dependencies]
+arrow2 = {workspace = true}
+pyo3 = {workspace = true, optional = true}
+
+[features]
+python = ["dep:pyo3"]
+
+[package]
+edition = {workspace = true}
+name = "common-arrow-ffi"
+version = {workspace = true}

src/daft-core/src/ffi.rs → src/common/arrow-ffi/src/lib.rs

@@ -2,11 +2,14 @@ use std::io::Cursor;
 
 use arrow2::{array::Array, datatypes::Field, ffi};
 
+#[cfg(feature = "python")]
 use pyo3::ffi::Py_uintptr_t;
+#[cfg(feature = "python")]
 use pyo3::prelude::*;
 
 pub type ArrayRef = Box<dyn Array>;
 
+#[cfg(feature = "python")]
 pub fn array_to_rust(arrow_array: &PyAny) -> PyResult<ArrayRef> {
     // prepare a pointer to receive the Array struct
     let array = Box::new(ffi::ArrowArray::empty());
@@ -28,7 +31,7 @@ pub fn array_to_rust(arrow_array: &PyAny) -> PyResult<ArrayRef> {
         Ok(array)
     }
 }
-
+#[cfg(feature = "python")]
 pub fn to_py_array(array: ArrayRef, py: Python, pyarrow: &PyModule) -> PyResult<PyObject> {
     let schema = Box::new(ffi::export_field_to_c(&Field::new(
         "",
@@ -53,6 +56,7 @@ pub fn to_py_array(array: ArrayRef, py: Python, pyarrow: &PyModule) -> PyResult<
     Ok(array.to_object(py))
 }
 
+#[cfg(feature = "python")]
 pub fn field_to_py(
     field: &arrow2::datatypes::Field,
     py: Python,
@@ -69,6 +73,7 @@ pub fn field_to_py(
     Ok(field.to_object(py))
 }
 
+#[cfg(feature = "python")]
 pub fn dtype_to_py(
     dtype: &arrow2::datatypes::DataType,
     py: Python,

src/common/daft-config/src/lib.rs

@@ -2,9 +2,6 @@
 use common_io_config::IOConfig;
 use serde::{Deserialize, Serialize};
 
-/// Environment variables for Daft to use when formatting displays.
-pub const BOLD_TABLE_HEADERS_IN_DISPLAY: &str = "DAFT_BOLD_TABLE_HEADERS";
-
 /// Configurations for Daft to use during the building of a Dataframe's plan.
 ///
 /// 1. Creation of a Dataframe including any file listing and schema inference that needs to happen. Note

src/common/display/Cargo.toml

@@ -1,4 +1,5 @@
 [dependencies]
+comfy-table = {workspace = true}
 indexmap = {workspace = true}
 pyo3 = {workspace = true, optional = true}
 terminal_size = {version = "0.3.0"}

src/common/display/src/lib.rs

@@ -1,5 +1,7 @@
+#![feature(let_chains)]
 pub mod ascii;
 pub mod mermaid;
+pub mod table_display;
 pub mod tree;
 pub mod utils;