check_syntax

#!/bin/bash

# Copyright (c) 2008-2026 the MRtrix3 contributors.
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
#
# Covered Software is provided under this License on an "as is"
# basis, without warranty of any kind, either expressed, implied, or
# statutory, including, without limitation, warranties that the
# Covered Software is free of defects, merchantable, fit for a
# particular purpose or non-infringing.
# See the Mozilla Public License v. 2.0 for more details.
#
# For more details, see http://www.mrtrix.org/.

LOG=syntax.log
echo -n "Checking syntax... "
echo "Checking syntax..." > $LOG
echo "" >> $LOG

grep=grep
v=`grep --version`
if [[ "$OSTYPE" == darwin* ]] && [[ $v == *"BSD"* ]]; then
  if ! hash ggrep 2>/dev/null; then
    echo 'Aborting, this script requires gnu-grep which you can install for instance via "brew install grep"'
    exit 1
  else
    grep=ggrep
  fi
fi

retval=0

rm -f .check_syntax1.tmp .check_syntax2.tmp .check_syntax3.tmp .check_syntax4.tmp

paths=()
for dir in src include tests examples; do
  if [[ -d "$dir" ]]; then
    paths+=("$dir")
  fi
done

if [[ ${#paths[@]} -eq 0 ]]; then
  echo "No source directories found."
  echo "no issues detected" >> $LOG
  exit 0
fi

for f in $(find "${paths[@]}" -type f \( -name '*.h' -o -name '*.hpp' -o -name '*.cpp' -o -name '*.cxx' -o -name '*.cc' -o -name '*.tpp' \) | sort); do

######################################################################
# Version of source code file omitting lines nominated to be ignored #
######################################################################
  cat $f | \
  $grep -vP '//.*\bcheck_syntax\s+off' > .check_syntax1.tmp

# Check for use of #define for constants
# Intended to catch integers, floats, scientific notation, hexadecimal, bitwise, and strings
  res=$(
    cat .check_syntax1.tmp | \
    $grep -Po '^#define\s+[a-zA-Z_][a-zA-Z0-9_]*\s+(0x[\dA-F]+|0b[01]+|\".*\"|[-+]?(?:[0-9]+\.?[0-9]*|\.[0-9]+)(?:[eE][-+]?[0-9]+)?)'
  )

# detect deprecated use of "#ifdef __headerpath__"
  res="$res"$(
    cat .check_syntax1.tmp | \
    perl -pe 's|//.*$||' | \
    tr '\n' ' ' | \
    perl -pe 's|\s+| |g' | \
    perl -pe 's|/\*.*?\*/||g' |
    $grep -Po '\#ifndef\s+__.*__\s+\#define\s+__.*__'
  )

#############################################################
# Process the file to strip macros and single-line comments #
#############################################################
  cat .check_syntax1.tmp | \
  $grep -v '^#' | \
  perl -pe 's|//.*$||' > .check_syntax2.tmp

######################################
# Further processing of file content #
######################################
  cat .check_syntax2.tmp | \
# remove all newlines to make file one long line:
  tr '\n' ' ' | \
# remove any duplicate spaces:
  perl -pe 's|\s+| |g' | \
# remove C-style comments:
  perl -pe 's|/\*.*?\*/||g' > .check_syntax3.tmp

# Detect any instances of definition of C-style arrays
# Note: Need to use version without removal of quoted strings
#   so that keyval["key"] isn't a hit
  res="$res"$(
    cat .check_syntax3.tmp | \
    $grep -Po '\b\w+(::\w+)*(?<!\breturn)(?<!\bnew)\s\w+(\[\d*\])+\s*[=;,]'
  )

#########################
# Remove quoted strings #
#########################
  cat .check_syntax3.tmp | \
  perl -pe 's/(")(\\"|.)*?"//g' > .check_syntax4.tmp

# - Detect any instances of char* or char item[],
#   which does not look like a cast for compatibility with external code
  res="$res"$(
    cat .check_syntax4.tmp | \
    $grep -Po '(const\s+|)char(\s?\*([\s]*const|)\s?(?![>\(\)])|\s+[a-zA-Z_][a-zA-Z0-9_]*\[(\d*\]|))'
  )

# - Detect any instances of C-style string manipulation functions
#   (need to permit strerror() for interfacing with external libraries)
  res="$res"$(
    cat .check_syntax4.tmp | \
    $grep -Po '\b(strcpy|strncpy|strcat|strncat|strxfrm|strlen|strcmp|strncmp|strcoll|strchr|strrchr|strspn|strcspn|strpbrk|strstr|strtok|wcscpy|wcsncpy|wcscat|wcsncat|wcsxfrm|wcslen|wcscmp|wcsncmp|wcscoll|wcschr|wcsrchr|wcsspn|wcscspn|wcspbrk|wcsstr|wcstok)\s*\('
  )

# - Detect namespaces that could have been nested
  res="$res"$(
    cat .check_syntax4.tmp | \
    $grep -Po '\bnamespace [\w\:]+\s*\{(namespace [\w\:]+\s*\{)+'
  )

# - Detect any instances of "using namespace std;":
  res="$res"$(
    cat .check_syntax4.tmp | \
    $grep -Po '\busing\snamespace\sstd\s?;'
  )

# - Detect any instances of C-style casts
  res="$res"$(
    cat .check_syntax4.tmp | \
    $grep -Po '(\((?!void\))[a-zA-Z][a-zA-Z0-9_]*\)[a-zA-Z][a-zA-Z0-9_]*|\([a-zA-Z][a-zA-Z0-9_]*\s?\*(\s?const)?\)[a-zA-Z][a-zA-Z0-9_]*|(?<!\bstd::function<)\b(GLint|GLfloat|c?float|c?double|(default|value|index)_type|[^\w_](unsigned\s+)?int|u?int(8|16|32|64)_t|s?size_t|ValueType|(?<!Scalar)::Scalar)\(\(*\**(?![\d\.]*\)))'
  )

# - Detect any instances of macros NULL, NAN, INFINITY
  res="$res"$(
    cat .check_syntax4.tmp | \
    $grep -Po '\b(NAN|INFINITY|NULL)\b'
  )

# delete intermediate files
rm -f .check_syntax1.tmp .check_syntax2.tmp .check_syntax3.tmp .check_syntax4.tmp

# if anything is left after that, show it:
  if [[ ! -z $res ]]; then
    echo "################################### $f" >> $LOG
    echo "$res" >> $LOG
    retval=1
  fi

done


# set exit code:
if [[ $retval == 0 ]]; then
  echo "OK"
  echo "no issues detected" >> $LOG
else
  echo "FAIL (see syntax.log for details)"

  echo "" >> $LOG
  echo "Please check the following syntax requirements:
  - Use #pragma once rather than #ifndef __headername__;
  - Use nested namespaces rather than sequentially-defined namespaces;
  - Define numerical constants using constexpr rather than preprocessor macros;
  - Use static_cast<>() rather than C-style casts;
  - Use std::string (and optionally std::string_view) rather than C-style char* and relevant functions;
  - Do not use \"using namespace std\";
  - Use std::numeric_limits<> rather than macros NAN / INFINITY;
  - Use nullptr rather than NULL macro;
  - Do not use C-style arrays (replace with eg. std::array<>)." >> $LOG
  exit 1
fi