flesh out yaml parser.

yaml.h

@@ -0,0 +1,144 @@
+#ifndef YAML_H
+#define YAML_H
+
+#include <stdlib.h>
+
+typedef enum {
+    YAML_TYPE_STRING,  /**< A value that represents a string. */
+    YAML_TYPE_NUMBER,  /**< A value that represents a number. */
+    YAML_TYPE_OBJECT,  /**< A value that represents an object. */
+    YAML_TYPE_ARRAY,   /**< A value that represents an array. */
+    YAML_TYPE_TRUE,    /**< A value that represents true. */
+    YAML_TYPE_FALSE,   /**< A value that represents false. */
+    YAML_TYPE_NULL,    /**< A value that represents null. */
+} yaml_type_t;
+
+typedef struct {
+    void *data;
+    yaml_type_t type;
+} yaml_value_t;
+
+typedef struct {
+    const char *data;
+    size_t length;
+} yaml_string_t;
+
+typedef struct {
+    const char *data;
+    size_t length;
+} yaml_number_t;
+
+typedef struct yaml_object_field_s {
+    yaml_string_t *name;
+    yaml_value_t *value;
+
+    struct yaml_object_field_s *next;
+} yaml_object_field_t;
+
+typedef struct {
+    yaml_object_field_t *head;
+    size_t count;
+} yaml_object_t;
+
+typedef struct yaml_array_element_s {
+    yaml_value_t *value;
+    
+    struct yaml_array_element_s *next;
+} yaml_array_element_t;
+
+typedef struct {
+    yaml_array_element_t *head;
+    size_t count;
+} yaml_array_t;
+
+/**
+ * Parse a UTF-8 encoded string into a value object.
+ *
+ * Returns `NULL` if parsing fails.
+ */
+yaml_value_t *yaml_parse(const void *, size_t);
+
+/**
+ * Traverse the tree to retrieve a specific sub-value from a root value.
+ *
+ * Returns `NULL` if the requested sub-value does not exist.
+ */
+yaml_value_t *yaml_get(const yaml_value_t *, const char *);
+
+/**
+ * Access a value object as a string.
+ *
+ * Returns `NULL` if the value is not a string.
+ */
+yaml_string_t *yaml_value_as_string(const yaml_value_t *);
+
+/**
+ * Access a value object as a number.
+ *
+ * Returns `NULL` if the value is not a number.
+ */
+yaml_number_t *yaml_value_as_number(const yaml_value_t *);
+
+/**
+ * Access a value object as an object.
+ *
+ * Returns `NULL` if the value is not an object.
+ */
+yaml_object_t *yaml_value_as_object(const yaml_value_t *);
+
+/**
+ * Access a value object as an array.
+ *
+ * Returns `NULL` if the value is not an array.
+ */
+yaml_array_t *yaml_value_as_array(const yaml_value_t *);
+
+/**
+ * Return a string describing the most recently encountered error.
+ *
+ * Returns `NULL` if no error has been encountered.
+ */
+const char *yaml_error(void);
+
+#endif /* YAML_H */
+
+#ifdef YAML_IMPLEMENTATION
+
+char error_message[4096];
+
+yaml_value_t *yaml_parse(const void *content, size_t length) {
+    /* TODO */
+    return NULL;
+}
+
+yaml_value_t *yaml_get(const yaml_value_t *root, const char *path) {
+    /* TODO */
+    return NULL;
+}
+
+yaml_string_t *yaml_value_as_string(const yaml_value_t *value) {
+    /* TODO */
+    return NULL;
+}
+
+yaml_number_t *yaml_value_as_number(const yaml_value_t *value) {
+    /* TODO */
+    return NULL;
+}
+
+yaml_object_t *yaml_object_as_object(const yaml_value_t *value) {
+    /* TODO */
+    return NULL;
+}
+
+yaml_array_t *yaml_object_as_array(const yaml_value_t *value) {
+    /* TODO */
+    return NULL;
+}
+
+const char *yaml_error(void) {
+    if (error_message[0] == '\0') return NULL;
+    return error_message;
+}
+
+#endif /* YAML_IMPLEMENTATION */