Merge #7234 'built-in expression parser'

1 files changed, 244 insertions, 0 deletions

diff --git a/src/nvim/viml/parser/parser.h b/src/nvim/viml/parser/parser.h
new file mode 100644
index 0000000000..7ac49709d8
--- /dev/null
+++ b/src/nvim/viml/parser/parser.h
@@ -0,0 +1,244 @@
+#ifndef NVIM_VIML_PARSER_PARSER_H
+#define NVIM_VIML_PARSER_PARSER_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <assert.h>
+
+#include "nvim/lib/kvec.h"
+#include "nvim/func_attr.h"
+#include "nvim/mbyte.h"
+#include "nvim/memory.h"
+
+/// One parsed line
+typedef struct {
+  const char *data;  ///< Parsed line pointer
+  size_t size;  ///< Parsed line size
+  bool allocated;  ///< True if line may be freed.
+} ParserLine;
+
+/// Line getter type for parser
+///
+/// Line getter must return {NULL, 0} for EOF.
+typedef void (*ParserLineGetter)(void *cookie, ParserLine *ret_pline);
+
+/// Parser position in the input
+typedef struct {
+  size_t line;  ///< Line index in ParserInputReader.lines.
+  size_t col;  ///< Byte index in the line.
+} ParserPosition;
+
+/// Parser state item.
+typedef struct {
+  enum {
+    kPTopStateParsingCommand = 0,
+    kPTopStateParsingExpression,
+  } type;
+  union {
+    struct {
+      enum {
+        kExprUnknown = 0,
+      } type;
+    } expr;
+  } data;
+} ParserStateItem;
+
+/// Structure defining input reader
+typedef struct {
+  /// Function used to get next line.
+  ParserLineGetter get_line;
+  /// Data for get_line function.
+  void *cookie;
+  /// All lines obtained by get_line.
+  kvec_withinit_t(ParserLine, 4) lines;
+  /// Conversion, for :scriptencoding.
+  vimconv_T conv;
+} ParserInputReader;
+
+/// Highlighted region definition
+///
+/// Note: one chunk may highlight only one line.
+typedef struct {
+  ParserPosition start;  ///< Start of the highlight: line and column.
+  size_t end_col;  ///< End column, points to the start of the next character.
+  const char *group;  ///< Highlight group.
+} ParserHighlightChunk;
+
+/// Highlighting defined by a parser
+typedef kvec_withinit_t(ParserHighlightChunk, 16) ParserHighlight;
+
+/// Structure defining parser state
+typedef struct {
+  /// Line reader.
+  ParserInputReader reader;
+  /// Position up to which input was parsed.
+  ParserPosition pos;
+  /// Parser state stack.
+  kvec_withinit_t(ParserStateItem, 16) stack;
+  /// Highlighting support.
+  ParserHighlight *colors;
+  /// True if line continuation can be used.
+  bool can_continuate;
+} ParserState;
+
+static inline void viml_parser_init(
+    ParserState *const ret_pstate,
+    const ParserLineGetter get_line, void *const cookie,
+    ParserHighlight *const colors)
+  REAL_FATTR_ALWAYS_INLINE REAL_FATTR_NONNULL_ARG(1, 2);
+
+/// Initialize a new parser state instance
+///
+/// @param[out]  ret_pstate  Parser state to initialize.
+/// @param[in]  get_line  Line getter function.
+/// @param[in]  cookie  Argument for the get_line function.
+/// @param[in]  colors  Where to save highlighting. May be NULL if it is not
+///                     needed.
+static inline void viml_parser_init(
+    ParserState *const ret_pstate,
+    const ParserLineGetter get_line, void *const cookie,
+    ParserHighlight *const colors)
+{
+  *ret_pstate = (ParserState) {
+    .reader = {
+      .get_line = get_line,
+      .cookie = cookie,
+      .conv = MBYTE_NONE_CONV,
+    },
+    .pos = { 0, 0 },
+    .colors = colors,
+    .can_continuate = false,
+  };
+  kvi_init(ret_pstate->reader.lines);
+  kvi_init(ret_pstate->stack);
+}
+
+static inline void viml_parser_destroy(ParserState *const pstate)
+  REAL_FATTR_NONNULL_ALL REAL_FATTR_ALWAYS_INLINE;
+
+/// Free all memory allocated by the parser on heap
+///
+/// @param  pstate  Parser state to free.
+static inline void viml_parser_destroy(ParserState *const pstate)
+{
+  for (size_t i = 0; i < kv_size(pstate->reader.lines); i++) {
+    ParserLine pline = kv_A(pstate->reader.lines, i);
+    if (pline.allocated) {
+      xfree((void *)pline.data);
+    }
+  }
+  kvi_destroy(pstate->reader.lines);
+  kvi_destroy(pstate->stack);
+}
+
+static inline void viml_preader_get_line(ParserInputReader *const preader,
+                                         ParserLine *const ret_pline)
+  REAL_FATTR_NONNULL_ALL;
+
+/// Get one line from ParserInputReader
+static inline void viml_preader_get_line(ParserInputReader *const preader,
+                                         ParserLine *const ret_pline)
+{
+  ParserLine pline;
+  preader->get_line(preader->cookie, &pline);
+  if (preader->conv.vc_type != CONV_NONE && pline.size) {
+    ParserLine cpline = {
+      .allocated = true,
+      .size = pline.size,
+    };
+    cpline.data = (char *)string_convert(&preader->conv,
+                                         (char_u *)pline.data,
+                                         &cpline.size);
+    if (pline.allocated) {
+      xfree((void *)pline.data);
+    }
+    pline = cpline;
+  }
+  kvi_push(preader->lines, pline);
+  *ret_pline = pline;
+}
+
+static inline bool viml_parser_get_remaining_line(ParserState *const pstate,
+                                                  ParserLine *const ret_pline)
+  REAL_FATTR_ALWAYS_INLINE REAL_FATTR_WARN_UNUSED_RESULT REAL_FATTR_NONNULL_ALL;
+
+/// Get currently parsed line, shifted to pstate->pos.col
+///
+/// @param  pstate  Parser state to operate on.
+///
+/// @return True if there is a line, false in case of EOF.
+static inline bool viml_parser_get_remaining_line(ParserState *const pstate,
+                                                  ParserLine *const ret_pline)
+{
+  const size_t num_lines = kv_size(pstate->reader.lines);
+  if (pstate->pos.line == num_lines) {
+    viml_preader_get_line(&pstate->reader, ret_pline);
+  } else {
+    *ret_pline = kv_last(pstate->reader.lines);
+  }
+  assert(pstate->pos.line == kv_size(pstate->reader.lines) - 1);
+  if (ret_pline->data != NULL) {
+    ret_pline->data += pstate->pos.col;
+    ret_pline->size -= pstate->pos.col;
+  }
+  return ret_pline->data != NULL;
+}
+
+static inline void viml_parser_advance(ParserState *const pstate,
+                                       const size_t len)
+  REAL_FATTR_ALWAYS_INLINE REAL_FATTR_NONNULL_ALL;
+
+/// Advance position by a given number of bytes
+///
+/// At maximum advances to the next line.
+///
+/// @param  pstate  Parser state to advance.
+/// @param[in]  len  Number of bytes to advance.
+static inline void viml_parser_advance(ParserState *const pstate,
+                                       const size_t len)
+{
+  assert(pstate->pos.line == kv_size(pstate->reader.lines) - 1);
+  const ParserLine pline = kv_last(pstate->reader.lines);
+  if (pstate->pos.col + len >= pline.size) {
+    pstate->pos.line++;
+    pstate->pos.col = 0;
+  } else {
+    pstate->pos.col += len;
+  }
+}
+
+static inline void viml_parser_highlight(ParserState *const pstate,
+                                         const ParserPosition start,
+                                         const size_t end_col,
+                                         const char *const group)
+  REAL_FATTR_ALWAYS_INLINE REAL_FATTR_NONNULL_ALL;
+
+/// Record highlighting of some region of text
+///
+/// @param  pstate  Parser state to work with.
+/// @param[in]  start  Start position of the highlight.
+/// @param[in]  len  Highlighting chunk length.
+/// @param[in]  group  Highlight group.
+static inline void viml_parser_highlight(ParserState *const pstate,
+                                         const ParserPosition start,
+                                         const size_t len,
+                                         const char *const group)
+{
+  if (pstate->colors == NULL || len == 0) {
+    return;
+  }
+  assert(kv_size(*pstate->colors) == 0
+         || kv_Z(*pstate->colors, 0).start.line < start.line
+         || kv_Z(*pstate->colors, 0).end_col <= start.col);
+  kvi_push(*pstate->colors, ((ParserHighlightChunk) {
+      .start = start,
+      .end_col = start.col + len,
+      .group = group,
+  }));
+}
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "viml/parser/parser.h.generated.h"
+#endif
+
+#endif  // NVIM_VIML_PARSER_PARSER_H