Add keyed lists and text comparison

A list state may name a key field of its record (the flags word of its
entry: field + 1). A keyed list keeps its items in key order, numbers by
value and texts by their bytes, each key once: LIST_APPEND places an item
by halving and fails with the new fault exists (PURE_CONFLICT) when the
key is there; LIST_FIND gives the index of a key's item and LIST_HAS
whether it is there. The verifier refuses inserting by position and
changing a key. Maps, sets and sorted maps are one list with an order
rule, so tables, filters, folds, indices, storage and replacement stay
as they are.

A module that opens over a list not in its key order (one that was not
keyed, keyed by another field, or stored so) puts it in order, moves its
indices with their items and stores it again; two items with one key
refuse the module rather than drop one.

TEXT_COMPARE compares two texts by their bytes under one of the six
relations.

1 files changed, 10 insertions, 2 deletions

diff --git a/prototypes/connections/module.h b/prototypes/connections/module.h
index 4264710..09a8540 100644
--- a/prototypes/connections/module.h
+++ b/prototypes/connections/module.h
@@ -37,7 +37,7 @@ typedef enum {
     PURE_OP_LIST_COUNT, PURE_OP_LIST_APPEND, PURE_OP_LIST_INSERT, PURE_OP_LIST_REMOVE,
     PURE_OP_ITEM_GET, PURE_OP_ITEM_SET, PURE_OP_INDEX_LOAD, PURE_OP_INDEX_STORE,
     PURE_OP_INDEX_MOVE, PURE_OP_INDEX_FIRST, PURE_OP_INDEX_LAST, PURE_OP_INDEX_NUM, PURE_OP_ROW,
-    PURE_OP_PICK, PURE_OP_SLIDE, PURE_OP_FOLD,
+    PURE_OP_PICK, PURE_OP_SLIDE, PURE_OP_FOLD, PURE_OP_TEXT_COMPARE, PURE_OP_LIST_FIND, PURE_OP_LIST_HAS,
     PURE_OP_COUNT
 } PureOpcode;
 /* FOLD's argument: the kind (bits 0-7), the list state (8-15) and the length
@@ -46,6 +46,9 @@ typedef enum {
  * max and min take a value and an include flag from their block; first gives
  * the index of the first item whose block leaves a non-zero number. */
 typedef enum { PURE_FOLD_COUNT, PURE_FOLD_SUM, PURE_FOLD_MAX, PURE_FOLD_MIN, PURE_FOLD_FIRST } PureFold;
+/* TEXT_COMPARE's argument: the relation, in the order of the number
+ * comparisons (LT LE GT GE EQ NE); texts order by their bytes. */
+typedef enum { PURE_LESS, PURE_LESS_EQUAL, PURE_GREATER, PURE_GREATER_EQUAL, PURE_EQUAL, PURE_NOT_EQUAL } PureRelation;
 
 typedef enum { PURE_KIND_KEY = 1, PURE_KIND_MESSAGE = 2, PURE_KIND_TEXT = 3 } PureInputKind;
 typedef enum { PURE_FIELD_U32 = 1, PURE_FIELD_BYTES = 2 } PureFieldType;
@@ -61,9 +64,11 @@ enum { PURE_CURSOR_STAYS = 1 };
 typedef enum { PURE_VIEW_NUM = 0, PURE_VIEW_TEXT = 1, PURE_VIEW_TABLE = 2 } PureViewType;
 typedef enum { PURE_UNIT_CHAR = 0, PURE_UNIT_LINE = 1 } PureUnit;
 typedef enum { PURE_EDGE_DOWN, PURE_EDGE_UP } PureEdge;
+/* EXISTS: an item with that key is already in the keyed list (the event
+ * reports PURE_CONFLICT). */
 typedef enum {
     PURE_FAULT_NONE, PURE_FAULT_DIVIDE, PURE_FAULT_NON_FINITE, PURE_FAULT_CLAMP,
-    PURE_FAULT_LIMIT, PURE_FAULT_NOT_FOUND, PURE_FAULT_ENCODING
+    PURE_FAULT_LIMIT, PURE_FAULT_NOT_FOUND, PURE_FAULT_ENCODING, PURE_FAULT_EXISTS
 } PureFault;
 
 typedef struct { double value; uint32_t arg; uint8_t op; } PureOp;
@@ -91,6 +96,9 @@ typedef struct {
     uint8_t state_type[PURE_MODULE_STATES];
     uint16_t state_ref[PURE_MODULE_STATES]; /* text: constant; cursor: text; list: record; index: list */
     uint8_t state_flags[PURE_MODULE_STATES]; /* cursor: PURE_CURSOR_STAYS */
+    /* A keyed list: its key field + 1 (0: none). Its items stay in key order
+     * (numbers by value, texts by bytes), each key once, and keys do not change. */
+    uint8_t state_key[PURE_MODULE_STATES];
     PureInputShape input[PURE_MODULE_INPUTS];
     PureField field[PURE_MODULE_FIELDS];
     double initial[PURE_MODULE_STATES];