1 files changed, 154 insertions, 0 deletions
diff --git a/src/formatter/utils.c b/src/formatter/utils.c
new file mode 100644
index 00000000..80445ec3
--- /dev/null
+++ b/src/formatter/utils.c
@@ -0,0 +1,154 @@
+// This file defines utility functions for autoformatting code
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "../ast.h"
+#include "../parse/context.h"
+#include "../stdlib/datatypes.h"
+#include "../stdlib/optionals.h"
+#include "../stdlib/tables.h"
+#include "../stdlib/text.h"
+#include "formatter.h"
+
+const Text_t single_indent = Text("    ");
+
+void add_line(Text_t *code, Text_t line, Text_t indent) {
+    if (code->length == 0) {
+        *code = line;
+    } else {
+        if (line.length > 0) *code = Texts(*code, "\n", indent, line);
+        else *code = Texts(*code, "\n");
+    }
+}
+
+OptionalText_t next_comment(Table_t comments, const char **pos, const char *end) {
+    for (const char *p = *pos; p < end; p++) {
+        const char **comment_end = Table$get(comments, &p, parse_comments_info);
+        if (comment_end) {
+            *pos = *comment_end;
+            return Text$from_strn(p, (int64_t)(*comment_end - p));
+        }
+    }
+    return NONE_TEXT;
+}
+
+bool range_has_comment(const char *start, const char *end, Table_t comments) {
+    OptionalText_t comment = next_comment(comments, &start, end);
+    return (comment.length >= 0);
+}
+
+CONSTFUNC int suggested_blank_lines(ast_t *first, ast_t *second) {
+    if (second == NULL) return 0;
+
+    for (;;) {
+        if (first->tag == Declare && Match(first, Declare)->value) {
+            first = Match(first, Declare)->value;
+        } else if (first->tag == DocTest && Match(first, DocTest)->expr && Match(first, DocTest)->expected == NULL) {
+            first = Match(first, DocTest)->expr;
+        } else break;
+    }
+
+    for (;;) {
+        if (second->tag == Declare && Match(second, Declare)->value) {
+            second = Match(second, Declare)->value;
+        } else if (second->tag == DocTest && Match(second, DocTest)->expr && Match(second, DocTest)->expected == NULL) {
+            second = Match(second, DocTest)->expr;
+        } else break;
+    }
+
+    switch (first->tag) {
+    case If:
+    case When:
+    case Repeat:
+    case While:
+    case For:
+    case Block:
+    case Defer:
+    case ConvertDef:
+    case FunctionDef:
+    case Lambda:
+    case StructDef:
+    case EnumDef:
+    case LangDef:
+    case Extend: return 1;
+    case Use: {
+        if (second->tag != Use) return 1;
+        break;
+    }
+    case Declare: {
+        DeclareMatch(decl, first, Declare);
+        if (decl->value) return suggested_blank_lines(decl->value, second);
+        break;
+    }
+    case Assign: {
+        DeclareMatch(assign, first, Assign);
+        for (ast_list_t *val = assign->values; val; val = val->next) {
+            if (suggested_blank_lines(val->ast, second) > 0) return 1;
+        }
+        break;
+    }
+    default: break;
+    }
+
+    switch (second->tag) {
+    case If:
+    case When:
+    case Repeat:
+    case While:
+    case For:
+    case Block:
+    case Defer:
+    case ConvertDef:
+    case FunctionDef:
+    case Lambda:
+    case StructDef:
+    case EnumDef:
+    case LangDef:
+    case Extend: return 1;
+    default: break;
+    }
+    return 0;
+}
+
+Text_t indent_code(Text_t code) {
+    if (code.length <= 0) return code;
+    return Texts(single_indent, Text$replace(code, Text("\n"), Texts("\n", single_indent)));
+}
+
+Text_t parenthesize(Text_t code, Text_t indent) {
+    if (Text$has(code, Text("\n"))) return Texts("(\n", indent, indent_code(code), "\n", indent, ")");
+    else return Texts("(", code, ")");
+}
+
+CONSTFUNC ast_t *unwrap_block(ast_t *ast) {
+    if (ast == NULL) return NULL;
+    while (ast->tag == Block && Match(ast, Block)->statements && Match(ast, Block)->statements->next == NULL) {
+        ast = Match(ast, Block)->statements->ast;
+    }
+    if (ast->tag == Block && Match(ast, Block)->statements == NULL) return NULL;
+    return ast;
+}
+
+OptionalText_t termify_inline(ast_t *ast, Table_t comments) {
+    if (range_has_comment(ast->start, ast->end, comments)) return NONE_TEXT;
+    switch (ast->tag) {
+    case BINOP_CASES:
+    case Not:
+    case Negative:
+    case HeapAllocate:
+    case StackReference: return parenthesize(format_inline_code(ast, comments), EMPTY_TEXT);
+    default: return format_inline_code(ast, comments);
+    }
+}
+
+Text_t termify(ast_t *ast, Table_t comments, Text_t indent) {
+    switch (ast->tag) {
+    case BINOP_CASES:
+    case Not:
+    case Negative:
+    case HeapAllocate:
+    case StackReference: return parenthesize(format_code(ast, comments, indent), indent);
+    default: return format_inline_code(ast, comments);
+    }
+}