pandemonium_engine/SCSCons/Tool/lex.py

# MIT License
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"""Tool-specific initialization for lex.

There normally shouldn't be any need to import this module directly.
It will usually be imported through the generic SCons.Tool.Tool()
selection method.
"""

import os.path
import sys

import SCons.Action
import SCons.Tool
import SCons.Util
import SCons.Warnings
from SCons.Platform.mingw import MINGW_DEFAULT_PATHS
from SCons.Platform.cygwin import CYGWIN_DEFAULT_PATHS
from SCons.Platform.win32 import CHOCO_DEFAULT_PATH

LexAction = SCons.Action.Action("$LEXCOM", "$LEXCOMSTR")

if sys.platform == 'win32':
    BINS = ['flex', 'lex', 'win_flex']
else:
    BINS = ["flex", "lex"]

def lexEmitter(target, source, env):
    sourceBase, sourceExt = os.path.splitext(SCons.Util.to_String(source[0]))

    if sourceExt == ".lm":           # If using Objective-C
        target = [sourceBase + ".m"] # the extension is ".m".

    # This emitter essentially tries to add to the target all extra
    # files generated by flex.

    # Different options that are used to trigger the creation of extra files.
    fileGenOptions = ["--header-file=", "--tables-file="]

    lexflags = env.subst("$LEXFLAGS", target=target, source=source)
    for option in SCons.Util.CLVar(lexflags):
        for fileGenOption in fileGenOptions:
            l = len(fileGenOption)
            if option[:l] == fileGenOption:
                # A file generating option is present, so add the
                # file name to the target list.
                fileName = option[l:].strip()
                target.append(fileName)
    return (target, source)

def get_lex_path(env, append_paths=False):
    """
    Find the path to the lex tool, searching several possible names

    Only called in the Windows case, so the default_path
    can be Windows-specific

    :param env: current construction environment
    :param append_paths: if set, add the path to the tool to PATH
    :return: path to lex tool, if found
    """
    for prog in BINS:
        bin_path = SCons.Tool.find_program_path(
            env,
            prog,
            default_paths=CHOCO_DEFAULT_PATH + MINGW_DEFAULT_PATHS + CYGWIN_DEFAULT_PATHS )
        if bin_path:
            if append_paths:
                env.AppendENVPath('PATH', os.path.dirname(bin_path))
            return bin_path

    SCons.Warnings.warn(
        SCons.Warnings.SConsWarning,
        'lex tool requested, but lex or flex binary not found in ENV PATH'
    )


def generate(env):
    """Add Builders and construction variables for lex to an Environment."""
    c_file, cxx_file = SCons.Tool.createCFileBuilders(env)

    # C
    c_file.add_action(".l", LexAction)
    c_file.add_emitter(".l", lexEmitter)

    c_file.add_action(".lex", LexAction)
    c_file.add_emitter(".lex", lexEmitter)

    # Objective-C
    cxx_file.add_action(".lm", LexAction)
    cxx_file.add_emitter(".lm", lexEmitter)

    # C++
    cxx_file.add_action(".ll", LexAction)
    cxx_file.add_emitter(".ll", lexEmitter)

    env["LEXFLAGS"] = SCons.Util.CLVar("")

    if sys.platform == 'win32':
        # ignore the return - we do not need the full path here
        _ = get_lex_path(env, append_paths=True)
        env["LEX"] = env.Detect(BINS)
        if not env.get("LEXUNISTD"):
            env["LEXUNISTD"] = SCons.Util.CLVar("")
        env["LEXCOM"] = "$LEX $LEXUNISTD $LEXFLAGS -t $SOURCES > $TARGET"
    else:
        env["LEX"] = env.Detect(BINS)
        env["LEXCOM"] = "$LEX $LEXFLAGS -t $SOURCES > $TARGET"

def exists(env):
    if sys.platform == 'win32':
        return get_lex_path(env)
    else:
        return env.Detect(BINS)

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