Add customize_fn attribute in derive macro and add styling information in readme

Author: devashishdxt

cli-table-derive/src/context/fields.rs

@@ -52,6 +52,7 @@ pub struct Field {
     pub bold: Option<LitBool>,
     pub order: usize,
     pub display_fn: Option<Ident>,
+    pub customize_fn: Option<Ident>,
     pub span: Span,
 }
 
@@ -71,6 +72,7 @@ impl Field {
         let mut bold = None;
         let mut order = None;
         let mut display_fn = None;
+        let mut customize_fn = None;
         let mut skip = None;
 
         let field_attributes = get_attributes(&field.attrs)?;
@@ -129,6 +131,14 @@ impl Field {
                         "Invalid value for #[table(display_fn = \"value\")]",
                     )),
                 }?);
+            } else if key.is_ident("customize_fn") {
+                customize_fn = Some(match value {
+                    Lit::Str(lit_str) => lit_str.parse::<Ident>(),
+                    bad => Err(Error::new_spanned(
+                        bad,
+                        "Invalid value for #[table(display_fn = \"value\")]",
+                    )),
+                }?);
             } else if key.is_ident("skip") {
                 skip = Some(match value {
                     Lit::Bool(lit_bool) => Ok(lit_bool),
@@ -173,6 +183,10 @@ impl Field {
             field_builder.display_fn(display_fn);
         }
 
+        if let Some(customize_fn) = customize_fn {
+            field_builder.customize_fn(customize_fn);
+        }
+
         Ok(Some(field_builder.build()))
     }
 
@@ -190,6 +204,7 @@ struct FieldBuilder {
     bold: Option<LitBool>,
     order: Option<usize>,
     display_fn: Option<Ident>,
+    customize_fn: Option<Ident>,
     span: Span,
 }
 
@@ -204,6 +219,7 @@ impl FieldBuilder {
             bold: None,
             order: None,
             display_fn: None,
+            customize_fn: None,
             span,
         }
     }
@@ -243,6 +259,11 @@ impl FieldBuilder {
         self
     }
 
+    fn customize_fn(&mut self, customize_fn: Ident) -> &mut Self {
+        self.customize_fn = Some(customize_fn);
+        self
+    }
+
     fn build(self) -> Field {
         let ident = self.ident;
         let justify = self.justify;
@@ -251,6 +272,7 @@ impl FieldBuilder {
         let bold = self.bold;
         let order = self.order.unwrap_or(usize::MAX);
         let display_fn = self.display_fn;
+        let customize_fn = self.customize_fn;
         let span = self.span;
 
         let title = self
@@ -266,6 +288,7 @@ impl FieldBuilder {
             bold,
             order,
             display_fn,
+            customize_fn,
             span,
         }
     }

cli-table-derive/src/lib.rs

@@ -15,7 +15,7 @@
 //!
 //! ## Simple usage
 //!
-//! ```rust,ignore
+//! ```rust
 //! use cli_table::{format::Justify, print_stdout, Cell, Style, Table};
 //!
 //! let table = vec![
@@ -104,6 +104,10 @@
 //!   column with `order = 1` and so on.
 //! - `display_fn`: Used to print types which do not implement `Display` trait. Usage `#[table(display_fn = "<func_name>")]`.
 //!   Signature of provided function should be `fn <func_name>(value: &<type>) -> impl Display`.
+//! - `customize_fn`: Used to customize style of a cell. Usage `#[table(customize_fn = "<func_name>")]`. Signature of
+//!   provided function should be `fn <func_name>(cell: CellStruct, value: &<type>) -> CellStruct`. This attribute can
+//!   be used when you want to change the formatting/style of a cell based on its contents. Note that this will
+//!   overwrite all the style settings done by other attributes.
 //! - `skip`: Used to skip a field from table. Usage: `#[table(skip)]`
 //!
 //! For more information on configurations available on derive macro, go to `cli-table/examples/struct.rs`.
@@ -115,6 +119,33 @@
 //!
 //! For more information on handling CSV values, go to `cli-table/examples/csv.rs`.
 //!
+//! # Styling
+//!
+//! Style of a table/cell can be modified by calling functions of [`Style`] trait. It is implementated by both
+//! [`TableStruct`] and [`CellStruct`].
+//!
+//! For individually formatting each cell of a table, `justify`, `align` and `padding` functions can be used from
+//! `CellStruct`.
+//!
+//! In addition to this, borders and separators of a table can be customized by calling `border` and `separator`
+//! functions in `TableStruct`. For example, to create a borderless table:
+//!
+//! ```rust,ignore
+//! use cli_table::{Cell, Table, TableStruct, format::{Justify, Border}, print_stdout};
+//!
+//! fn get_table() -> TableStruct {
+//!     vec![
+//!         vec!["Tom".cell(), 10.cell().justify(Justify::Right)],
+//!         vec!["Jerry".cell(), 15.cell().justify(Justify::Right)],
+//!         vec!["Scooby Doo".cell(), 20.cell().justify(Justify::Right)],
+//!     ]
+//!     .table()
+//! }
+//!
+//! let table = get_table().border(Border::builder().build()); // Attaches an empty border to the table
+//! assert!(print_stdout(table).is_ok());
+//! ```
+//!
 //! # Features
 //!
 //! - `derive`: Enables derive macro for creating tables using structs. **Enabled** by default.

cli-table-derive/src/table.rs

@@ -29,6 +29,7 @@ pub fn table(input: DeriveInput) -> Result<TokenStream> {
         let color = field.color;
         let bold = field.bold;
         let display_fn = field.display_fn;
+        let customize_fn = field.customize_fn;
         let span = field.span;
 
         let cell = match display_fn {
@@ -71,6 +72,12 @@ pub fn table(input: DeriveInput) -> Result<TokenStream> {
             };
         }
 
+        if let Some(customize_fn) = customize_fn {
+            row = quote_spanned! {span=>
+                #customize_fn (#row, &self. #ident)
+            };
+        }
+
         field_rows.push(row);
     }
 

cli-table/README.md

@@ -107,6 +107,10 @@ Below is the output of the table we created using derive macro:
   column with `order = 1` and so on.
 - `display_fn`: Used to print types which do not implement `Display` trait. Usage `#[table(display_fn = "<func_name>")]`.
   Signature of provided function should be `fn <func_name>(value: &<type>) -> impl Display`.
+- `customize_fn`: Used to customize style of a cell. Usage `#[table(customize_fn = "<func_name>")]`. Signature of
+  provided function should be `fn <func_name>(cell: CellStruct, value: &<type>) -> CellStruct`. This attribute can
+  be used when you want to change the formatting/style of a cell based on its contents. Note that this will
+  overwrite all the style settings done by other attributes.
 - `skip`: Used to skip a field from table. Usage: `#[table(skip)]`
 
 For more information on configurations available on derive macro, go to `cli-table/examples/struct.rs`.
@@ -118,6 +122,33 @@ use `TryFrom<&mut Reader> for TableStruct` trait implementation to convert `csv:
 
 For more information on handling CSV values, go to `cli-table/examples/csv.rs`.
 
+## Styling
+
+Style of a table/cell can be modified by calling functions of [`Style`] trait. It is implementated by both
+[`TableStruct`] and [`CellStruct`].
+
+For individually formatting each cell of a table, `justify`, `align` and `padding` functions can be used from
+`CellStruct`.
+
+In addition to this, borders and separators of a table can be customized by calling `border` and `separator`
+functions in `TableStruct`. For example, to create a borderless table:
+
+```rust
+use cli_table::{Cell, Table, TableStruct, format::{Justify, Border}, print_stdout};
+
+fn get_table() -> TableStruct {
+    vec![
+        vec!["Tom".cell(), 10.cell().justify(Justify::Right)],
+        vec!["Jerry".cell(), 15.cell().justify(Justify::Right)],
+        vec!["Scooby Doo".cell(), 20.cell().justify(Justify::Right)],
+    ]
+    .table()
+}
+
+let table = get_table().border(Border::builder().build()); // Attaches an empty border to the table
+assert!(print_stdout(table).is_ok());
+```
+
 ## Features
 
 - `derive`: Enables derive macro for creating tables using structs. **Enabled** by default.

cli-table/src/lib.rs

@@ -104,6 +104,10 @@
 //!   column with `order = 1` and so on.
 //! - `display_fn`: Used to print types which do not implement `Display` trait. Usage `#[table(display_fn = "<func_name>")]`.
 //!   Signature of provided function should be `fn <func_name>(value: &<type>) -> impl Display`.
+//! - `customize_fn`: Used to customize style of a cell. Usage `#[table(customize_fn = "<func_name>")]`. Signature of
+//!   provided function should be `fn <func_name>(cell: CellStruct, value: &<type>) -> CellStruct`. This attribute can
+//!   be used when you want to change the formatting/style of a cell based on its contents. Note that this will
+//!   overwrite all the style settings done by other attributes.
 //! - `skip`: Used to skip a field from table. Usage: `#[table(skip)]`
 //!
 //! For more information on configurations available on derive macro, go to `cli-table/examples/struct.rs`.
@@ -115,6 +119,33 @@
 //!
 //! For more information on handling CSV values, go to `cli-table/examples/csv.rs`.
 //!
+//! # Styling
+//!
+//! Style of a table/cell can be modified by calling functions of [`Style`] trait. It is implementated by both
+//! [`TableStruct`] and [`CellStruct`].
+//!
+//! For individually formatting each cell of a table, `justify`, `align` and `padding` functions can be used from
+//! `CellStruct`.
+//!
+//! In addition to this, borders and separators of a table can be customized by calling `border` and `separator`
+//! functions in `TableStruct`. For example, to create a borderless table:
+//!
+//! ```rust
+//! use cli_table::{Cell, Table, TableStruct, format::{Justify, Border}, print_stdout};
+//!
+//! fn get_table() -> TableStruct {
+//!     vec![
+//!         vec!["Tom".cell(), 10.cell().justify(Justify::Right)],
+//!         vec!["Jerry".cell(), 15.cell().justify(Justify::Right)],
+//!         vec!["Scooby Doo".cell(), 20.cell().justify(Justify::Right)],
+//!     ]
+//!     .table()
+//! }
+//!
+//! let table = get_table().border(Border::builder().build()); // Attaches an empty border to the table
+//! assert!(print_stdout(table).is_ok());
+//! ```
+//!
 //! # Features
 //!
 //! - `derive`: Enables derive macro for creating tables using structs. **Enabled** by default.

test-suite/tests/ui/title-string-value.stderr

@@ -1,5 +1,5 @@
-error: `title` only accepts `&str` values
- --> $DIR/title-string-value.rs:5:21
+error: Invalid value for #[table(title = "field_name")]
+ --> $DIR/title-string-value.rs:6:21
   |
-5 |     #[table(title = 1)]
+6 |     #[table(title = 1)]
   |                     ^