Compiler/Preprocessor: Difference between revisions
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The include command must be followed by whitespace and a double quoted string whose contents is the actual file to read. Includes should allow the inclusion of other files to a recursive limit of five active header files plus the original source file.
The define command must be followed by whitespace and a new macro name. Redefinition or overloading of the macro name is illegal. The same character convention for naming variables in the language is used for macro names. No whitespace is required in the arguments but is allowed between every token. When there are no parameters, both the definition or usage must either have an empty argument list or there must not be one. The empty list is required to avoid confusion when the definition needs parenthesizes to force precedence. If there is a close parenthesis, the whitespace trailing it is optional. Otherwise, it is required. From that point to end of line is the definition, whitespace removed from both the start and end of it. Whitespace within the definition between tokens must be maintained. Any names within the definition are treated as macro names first before it is assumed they are a variable in the language during the usage.
To make it easier to find, the usage will be within hashtags, and replaces its usage elsewhere in the files processed. These usages will be processed everywhere they are encountered without regard to the syntax of the sample language. The calling arguments replace the define's parameters as a simple string substitution. You may not assume the usage proceeds in an order to form complex combinations. Tokens detected during definition processing can remain separated during usage processing. If the contents within the double hashtags is not a valid macro usage, its entire text is written to the output as if it was not detected. It is not required to use the ending hashtag as the start of another macro usage. Both start and end hashtags must be on the same line.
Line 61:
=={{header|Julia}}==
<
""" If the line is a macro definition, add the macro to macros. """
Line 201:
runwithopts(preprocess)
</
=={{header|Phix}}==
No attempt to implement command line arguments, obviously trivial on desktop/Phix but not possible under pwa/p2js, aka within a browser.
<!--<
<span style="color: #000080;font-style:italic;">--
-- demo\rosetta\Compiler\preprocess.exw
Line 381:
<span style="color: #000080;font-style:italic;">--close_files()</span>
<!--</
{{out}}
<pre>
Line 395:
/* Use area, height, and width */
area = 6 * 5;
</pre>
=={{header|Python}}==
<syntaxhighlight lang="python">#!/usr/bin/env python
"""Rosetta Code compiler/preprocessor. Requires Python >= 3.7."""
import re
import sys
from typing import Dict
from typing import Iterator
from typing import List
from typing import NamedTuple
from typing import Optional
from typing import TextIO
from typing import Tuple
MAX_INCLUDE_DEPTH = 5
TOKEN_INCLUDE = "INCLUDE"
TOKEN_CONSTANT = "CONSTANT"
TOKEN_MACRO = "MACRO"
TOKEN_CALL = "CALL"
TOKEN_STRING = "STRING"
TOKEN_COMMENT = "COMMENT"
TOKEN_LITERAL = "LITERAL"
TOKEN_ILLEGAL = "ILLEGAL"
class Token(NamedTuple):
kind: str
name: str
params: str
expr: str
start: int
end: int
FILENAME_PATTERN = r"[_a-zA-Z][_a-zA-Z0-9\.]*"
IDENT_PATTERN = r"[_a-zA-Z][_a-zA-Z0-9]*"
PARAMS_PATTERN = r"[_a-zA-Z0-9\., \t]*?"
TOKEN_RULES = (
(
TOKEN_STRING,
r"\"[^\"\n]*?\"",
),
(
TOKEN_COMMENT,
r"/\*.*?\*/",
),
(
TOKEN_LITERAL,
r"[^#]+",
),
(
TOKEN_INCLUDE,
rf"^\#include[ \t]+\"(?P<filename>{FILENAME_PATTERN})\"\s*?$",
),
(
TOKEN_CONSTANT,
rf"^\#define[ \t]+(?P<constant>{IDENT_PATTERN}) +(?P<constant_expr>.*?)$",
),
(
TOKEN_MACRO,
rf"^\#define[ \t](?P<macro>{IDENT_PATTERN})"
rf"\((?P<macro_params>{PARAMS_PATTERN})\) +(?P<macro_expr>.*?)$",
),
(
TOKEN_CALL,
rf"\#(?P<call>{IDENT_PATTERN})\((?P<call_params>{PARAMS_PATTERN})\)\#",
),
(
TOKEN_ILLEGAL,
r".",
),
)
RE_TOKENS = re.compile(
"|".join(f"(?P<{name}>{pattern})" for name, pattern in TOKEN_RULES),
re.MULTILINE,
)
class PreprocessorError(Exception):
def __init__(
self,
*args: object,
source: str,
filename: str,
token: Token,
) -> None:
super().__init__(*args)
self.source = source
self.token = token
self.filename = filename
def __str__(self) -> str:
msg = super().__str__()
line_num = self.source[: self.token.start].count("\n") + 1
return f"{msg} ({self.filename}:{line_num})"
def tokenize(source: str, filename: str) -> Iterator[Token]:
for match in RE_TOKENS.finditer(source):
kind = match.lastgroup
if kind in (TOKEN_LITERAL, TOKEN_COMMENT, TOKEN_STRING):
yield Token(
TOKEN_LITERAL,
"",
"",
match.group(),
match.start(),
match.end(),
)
elif kind == TOKEN_INCLUDE:
yield Token(
TOKEN_INCLUDE,
"",
"",
match.group("filename"),
match.start(),
match.end(),
)
elif kind == TOKEN_CONSTANT:
yield Token(
kind,
match.group("constant"),
"",
match.group("constant_expr"),
match.start(),
match.end(),
)
elif kind == TOKEN_MACRO:
yield Token(
kind,
match.group("macro"),
match.group("macro_params"),
match.group("macro_expr"),
match.start(),
match.end(),
)
elif kind == TOKEN_CALL:
yield Token(
kind,
match.group("call"),
match.group("call_params"),
"",
match.start(),
match.end(),
)
elif kind == TOKEN_ILLEGAL:
# Probably part of an invalid macro call
yield Token(
TOKEN_LITERAL,
"",
"",
match.group(),
match.start(),
match.end(),
)
else:
raise PreprocessorError(
f"unexpected token kind {kind} ({match.group()!r})",
source=source,
filename=filename,
token=Token(
TOKEN_ILLEGAL,
"",
"",
match.group(),
match.start(),
match.end(),
),
)
def preprocess(
source: str,
filename: str,
stream: TextIO,
debug: bool = False,
constants: Optional[Dict[str, str]] = None,
include_depth: int = 0,
macros: Optional[Dict[str, Tuple[str, int]]] = None,
) -> None:
constants = constants if constants is not None else {}
include_depth = include_depth
macros = macros if macros is not None else {}
left_strip = False
for token in tokenize(source, filename):
if token.kind == TOKEN_LITERAL:
if left_strip:
stream.write(_lstrip_one(token.expr))
left_strip = False
else:
stream.write(token.expr)
elif token.kind == TOKEN_CONSTANT:
if debug:
stream.write(f"/* Define {token.name} as {token.expr} */\n")
if token.name in constants:
raise PreprocessorError(
f"illegal constant redefinition '{token.name}'",
source=source,
filename=filename,
token=token,
)
constants[token.name] = token.expr
left_strip = True
elif token.kind == TOKEN_INCLUDE:
if include_depth + 1 > MAX_INCLUDE_DEPTH:
raise PreprocessorError(
"maximum include depth reached",
source=source,
filename=filename,
token=token,
)
if debug:
stream.write(f"/* Include {token.expr} */\n")
with open(token.expr) as fd:
preprocess(
fd.read(),
filename,
stream,
debug,
constants,
include_depth + 1,
macros,
)
if debug:
stream.write(f"/* End {token.expr} */\n")
left_strip = True
elif token.kind == TOKEN_MACRO:
if debug:
stream.write(
f"/* Define {token.name}({token.params}) as {token.expr} */\n"
)
if token.name in macros:
raise PreprocessorError(
f"illegal macro redefinition '{token.name}'",
source=source,
filename=filename,
token=token,
)
params = parse_parameters(token.params)
expr = parse_expression(params, token.expr)
macros[token.name] = (expr, len(params))
left_strip = True
elif token.kind == TOKEN_CALL:
params = parse_parameters(token.params)
expr, n_args = macros.get(token.name, ("", 0))
if debug:
if params:
used = [token.name, *params]
stream.write(f"/* Use {', '.join(used[:-1])} and {used[-1]} */ ")
else:
stream.write(f"/* Use {token.name} */ ")
if len(params) != n_args:
print(token.name, len(params), n_args, macros)
stream.write(source[token.start : token.end])
else:
stream.write(
substitute_constants(
constants,
expr.format(*params),
)
)
left_strip = False
else:
raise PreprocessorError(
f"unknown token kind {token}",
source=source,
filename=filename,
token=token,
)
def parse_parameters(params: str) -> List[str]:
return [param.strip() for param in params.split(",")]
def parse_expression(params: List[str], expr: str) -> str:
_params = {p: str(i) for i, p in enumerate(params)}
pattern = "|".join(rf"\b{param}\b" for param in params)
return re.sub(
f"({pattern})",
lambda m: f"{{{_params[m.group(0)]}}}",
expr,
)
def substitute_constants(constants: Dict[str, str], expr: str) -> str:
pattern = "|".join(rf"\b{const}\b" for const in constants)
return re.sub(
f"({pattern})",
lambda m: constants[m.group(0)],
expr,
)
def _lstrip_one(s: str) -> str:
"""Strip at most one newline from the left of `s`."""
if s and s[0] == "\n":
return s[1:]
return s
if __name__ == "__main__":
import argparse
parser = argparse.ArgumentParser(description="Rosetta Code compiler preprocessor.")
parser.add_argument(
"infile",
nargs="?",
type=argparse.FileType("r"),
default=sys.stdin,
help="source file to preprocess, '-' means stdin (default: stdin)",
)
parser.add_argument(
"outfile",
nargs="?",
type=argparse.FileType("w"),
default=sys.stdout,
help="destination file (default: stdout)",
)
parser.add_argument(
"--debug",
"-d",
action="store_true",
help="enable debugging output (default: false)",
)
args = parser.parse_args()
preprocess(args.infile.read(), args.infile.name, args.outfile, debug=args.debug)
</syntaxhighlight>
{{out}}
Command line options. Show the help message and exit.
<pre>
$ ./preproc.py --help
usage: preproc.py [-h] [--debug] [infile] [outfile]
Rosetta Code compiler preprocessor.
positional arguments:
infile source file to preprocess, '-' means stdin (default: stdin)
outfile destination file (default: stdout)
options:
-h, --help show this help message and exit
--debug, -d enable debugging output (default: false)
</pre>
Where <code>Source.t</code> and <code>Header.h</code> contain the source code shown in the task description.
<pre>
$ ./preproc.py Source.t
area = 6 * 5;
</pre>
And with debugging enabled. Notice debug output appears immediately before a macro call rather than on the line above.
<pre>
$ ./preproc.py source.t --debug
/* Include Header.h */
/* Define area(h, w) as h * w */
/* End Header.h */
/* Define width as 5 */
/* Define height as 6 */
area = /* Use area, height and width */ 6 * 5;
</pre>
And piped to the lexer defined in the Lexical Analysis task.
<pre>
$ ./preproc.py source.t | ./compiler_lex.py
1 1 Identifier area
1 6 Op_assign
1 8 Integer 6
1 10 Op_multiply
1 12 Integer 5
1 13 Semicolon
2 1 End_of_input
</pre>
Line 409 ⟶ 802:
Note that the program errors out if there are any syntax or other errors when defining the macros.
<
import "./ioutil" for FileUtil, File, Input
import "./str" for Char
Line 587 ⟶ 980:
file.writeBytes("\n")
}
}</
{{out}}
Using the example files;
<pre>
$ wren-cli
How many lines are to be entered? : 4
Line 632 ⟶ 1,025:
{{out}}
<pre>
$ wren-cli
Output:
| |||