x-base.c File Reference

Implementation of the base environment object. More...

#include "x-base.h"

Macros
#define	nil   NULL
#define	pair(X, Y)   (x_mkspair(p_base, X_OBJ_FLAG_SHARED, (X), (Y)))
#define	atom(X)   (x_mksatom(p_base, X_OBJ_FLAG_SHARED, (X)))

Functions
x_obj_t *	x_base_make (x_obj_t *p_base, struct x_base_t base)
x_obj_t *	x_base_read (x_obj_t *p_base, x_obj_t *p_args)
x_obj_t *	x_base_write (x_obj_t *p_base, x_obj_t *p_args)

Detailed Description

Implementation of the base environment object.

Author

Jon Ruttan (jonru.nosp@m.ttan.nosp@m.@gmai.nosp@m.l.co.nosp@m.m)

Copyright

2021 Jon Ruttan @license MIT No Attribution (MIT-0)

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Macro Definition Documentation

atom

#define atom

(

X

)

(x_mksatom(p_base, X_OBJ_FLAG_SHARED, (X)))

nil

#define nil   NULL

pair

#define pair	(		X,
			Y
	)		(x_mkspair(p_base, X_OBJ_FLAG_SHARED, (X), (Y)))

Function Documentation

x_base_make()

x_obj_t * x_base_make	(	x_obj_t *	p_base,
		struct x_base_t	base
	)

Create a new base environment object.

Allocates and assembles the nested pair tree that holds all environment state. Every node is allocated with X_OBJ_FLAG_SHARED (via the local pair/atom macros) so the base tree is immune to garbage collection. Each leaf value is wrapped as pair(atom(value), nil) to form a one-element field stack (see x-base.h). Hook values passed as NULL produce (nil . nil) leaves (hook disabled). The tree layout matches the field accessor macros: x_base_field_filein() navigates to the filein leaf, x_base_field_hook_type_name() to the type_name hook, etc.

Parameters

p_base	Existing base for allocation context, or NULL for bootstrap.
base	Initialization parameters (file descriptors, hooks, etc.).

Returns

The newly created base object.

x_base_read()

x_obj_t * x_base_read	(	x_obj_t *	p_base,
		x_obj_t *	p_args
	)

Read data from the base's input file descriptor into an atom.

Uses the filein descriptor from the base environment, or falls back to STDIN_FILENO if the base is not initialized.

Parameters

p_base	Base (execution context).
p_args	Pair list: (destination-atom byte-count).

Returns

The destination atom on success, or NULL on read failure. On failure the byte-count atom is overwritten with the raw x_sys_read() result so the caller can tell end-of-stream (0) from a read error (negative): this layer has no error channel, and conflating the two turned transient read errors into silent input truncation (x-lang#170).

x_base_write()

x_obj_t * x_base_write	(	x_obj_t *	p_base,
		x_obj_t *	p_args
	)

Write data from an atom to the base's output or write buffer.

Checks the write_buf field first: if it holds a non-nil pair (pointer . position), data is memcpy'd into the buffer at the current position and the position is advanced. Otherwise, writes to the fileout file descriptor, falling back to STDOUT_FILENO if the base is not initialized.

Parameters

p_base	Base (execution context).
p_args	Pair list: (source-atom byte-count).

Returns

The source atom on success, or NULL on write failure.