GH-111485: Separate out parsing, analysis and code-gen phases of tier 1 code generator (GH-112299)

1 files changed, 111 insertions, 0 deletions

diff --git a/Tools/cases_generator/cwriter.py b/Tools/cases_generator/cwriter.py
new file mode 100644
index 0000000..0b7edd0
--- /dev/null
+++ b/Tools/cases_generator/cwriter.py
@@ -0,0 +1,111 @@
+from lexer import Token
+from typing import TextIO
+
+
+class CWriter:
+    "A writer that understands tokens and how to format C code"
+
+    last_token: Token | None
+
+    def __init__(self, out: TextIO, indent: int, line_directives: bool):
+        self.out = out
+        self.base_column = indent * 4
+        self.indents = [i * 4 for i in range(indent + 1)]
+        self.line_directives = line_directives
+        self.last_token = None
+        self.newline = True
+
+    def set_position(self, tkn: Token) -> None:
+        if self.last_token is not None:
+            if self.last_token.line < tkn.line:
+                self.out.write("\n")
+                if self.line_directives:
+                    self.out.write(f'#line {tkn.line} "{tkn.filename}"\n')
+                self.out.write(" " * self.indents[-1])
+            else:
+                gap = tkn.column - self.last_token.end_column
+                self.out.write(" " * gap)
+        elif self.newline:
+            self.out.write(" " * self.indents[-1])
+        self.last_token = tkn
+        self.newline = False
+
+    def emit_at(self, txt: str, where: Token) -> None:
+        self.set_position(where)
+        self.out.write(txt)
+
+    def maybe_dedent(self, txt: str) -> None:
+        parens = txt.count("(") - txt.count(")")
+        if parens < 0:
+            self.indents.pop()
+        elif "}" in txt or is_label(txt):
+            self.indents.pop()
+
+    def maybe_indent(self, txt: str) -> None:
+        parens = txt.count("(") - txt.count(")")
+        if parens > 0 and self.last_token:
+            offset = self.last_token.end_column - 1
+            if offset <= self.indents[-1] or offset > 40:
+                offset = self.indents[-1] + 4
+            self.indents.append(offset)
+        elif "{" in txt or is_label(txt):
+            self.indents.append(self.indents[-1] + 4)
+
+    def emit_text(self, txt: str) -> None:
+        self.out.write(txt)
+
+    def emit_multiline_comment(self, tkn: Token) -> None:
+        self.set_position(tkn)
+        lines = tkn.text.splitlines(True)
+        first = True
+        for line in lines:
+            text = line.lstrip()
+            if first:
+                spaces = 0
+            else:
+                spaces = self.indents[-1]
+                if text.startswith("*"):
+                    spaces += 1
+                else:
+                    spaces += 3
+            first = False
+            self.out.write(" " * spaces)
+            self.out.write(text)
+
+    def emit_token(self, tkn: Token) -> None:
+        if tkn.kind == "COMMENT" and "\n" in tkn.text:
+            return self.emit_multiline_comment(tkn)
+        self.maybe_dedent(tkn.text)
+        self.set_position(tkn)
+        self.emit_text(tkn.text)
+        self.maybe_indent(tkn.text)
+
+    def emit_str(self, txt: str) -> None:
+        self.maybe_dedent(txt)
+        if self.newline and txt:
+            if txt[0] != "\n":
+                self.out.write(" " * self.indents[-1])
+            self.newline = False
+        self.emit_text(txt)
+        if txt.endswith("\n"):
+            self.newline = True
+        self.maybe_indent(txt)
+        self.last_token = None
+
+    def emit(self, txt: str | Token) -> None:
+        if isinstance(txt, Token):
+            self.emit_token(txt)
+        elif isinstance(txt, str):
+            self.emit_str(txt)
+        else:
+            assert False
+
+    def start_line(self) -> None:
+        if not self.newline:
+            self.out.write("\n")
+        self.newline = True
+        self.last_token = None
+
+
+def is_label(txt: str) -> bool:
+    return not txt.startswith("//") and txt.endswith(":")