Function from_csv 

pub fn from_csv(csv: &str, type_name: &str, schema: &[&str]) -> Result<Document>

Parse CSV string into a HEDL document with default configuration.

This is the primary entry point for CSV parsing. It uses sensible defaults:

• Comma delimiter
• Headers expected in first row
• Whitespace trimming enabled
• 1 million row limit for security

Arguments

• csv - The CSV string to parse
• type_name - The HEDL type name for rows (e.g., “Person”)
• schema - Column names excluding the ‘id’ column (which is always first)

Returns

A Document containing a single matrix list with the parsed data, or an error if parsing fails.

Errors

Returns HedlError in the following cases:

• Syntax: Malformed CSV records or invalid UTF-8
• Schema: Missing ID column or field count mismatch
• Semantic: Empty ID field
• Security: Row count exceeds maximum (default 1M rows)

Type Inference

Values are automatically inferred from CSV text:

• Empty string or ~ → Value::Null
• true/false → Value::Bool
• Integer pattern → Value::Int (e.g., “42”, “-123”)
• Float pattern → Value::Float (e.g., “3.14”, “1.5e10”)
• Special floats: NaN, Infinity, -Infinity
• @id or @Type:id → Value::Reference
• $(expr) → Value::Expression
• [1,2,3] → Value::Tensor
• Otherwise → Value::String

Examples

Basic Usage

use hedl_csv::from_csv;
use hedl_core::Value;

let csv_data = "id,name,age\n1,Alice,30\n2,Bob,25";
let doc = from_csv(csv_data, "Person", &["name", "age"]).unwrap();

// Access the parsed data
let list = doc.get("persons").unwrap().as_list().unwrap();
assert_eq!(list.rows.len(), 2);
assert_eq!(list.rows[0].id, "1");

Mixed Type Inference

use hedl_csv::from_csv;
use hedl_core::Value;

let csv_data = "id,value\n1,42\n2,3.14\n3,true\n4,hello";
let doc = from_csv(csv_data, "Item", &["value"]).unwrap();

let list = doc.get("items").unwrap().as_list().unwrap();
assert!(matches!(list.rows[0].fields[1], Value::Int(42)));
assert!(matches!(list.rows[1].fields[1], Value::Float(f) if (f - 3.14).abs() < 0.001));
assert!(matches!(list.rows[2].fields[1], Value::Bool(true)));
assert!(matches!(list.rows[3].fields[1], Value::String(_)));

References

use hedl_csv::from_csv;

let csv_data = "id,owner\n1,@user1\n2,@User:alice";
let doc = from_csv(csv_data, "Item", &["owner"]).unwrap();

let list = doc.get("items").unwrap().as_list().unwrap();
let ref1 = list.rows[0].fields[1].as_reference().unwrap();
assert_eq!(ref1.id, "user1");
assert_eq!(ref1.type_name, None); // Local reference

let ref2 = list.rows[1].fields[1].as_reference().unwrap();
assert_eq!(ref2.id, "alice");
assert_eq!(ref2.type_name, Some("User".to_string())); // Qualified reference

Performance

• Streaming: Processes CSV row-by-row to minimize memory usage
• Memory bound: O(rows × columns) space complexity
• Time complexity: O(rows × columns) with efficient parsing

For very large files, consider using from_csv_reader for file I/O or increasing max_rows via from_csv_with_config.

See Also

• from_csv_with_config - For custom delimiters, row limits, etc.
• from_csv_reader - For parsing from files or network streams