rwx/sh/main.awk

function append(line) {
    if (doc) {
        doc = doc "\n"
    }
    doc = doc line
}

function output(name, type) {
    print name "  ← " type
    print doc
    exit
}

function reset() {
    doc = ""
}

BEGIN {
    RE_ANY = "(.*)"
    RE_CONST = "([_A-Z][_0-9A-Z]*)"
    RE_SET = "=.*"
    RE_SPACE = "[[:space:]]"
    RE_SPACES = RE_SPACE "*"
    RE_VAR = "([_a-z][_0-9a-z]*)"

    RE_BEGIN = "^"
    RE_END = RE_SPACES "$"
    RE_FUNC = RE_SPACES "\\(" RE_SPACES "\\)" RE_SPACES "{"

    RE_ALIAS = RE_BEGIN "#=" RE_SPACES RE_VAR RE_END
    RE_CLOSE = RE_BEGIN "}" RE_SPACES RE_END
    RE_CONSTANT = RE_BEGIN RE_CONST RE_SET RE_END
    RE_DOC = RE_BEGIN "#" RE_SPACE RE_ANY RE_END
    RE_FUNCTION = RE_BEGIN RE_VAR RE_FUNC RE_END
    RE_MODULE = RE_BEGIN "#." RE_SPACES RE_ANY RE_END
    RE_SHEBANG = RE_BEGIN "#!" RE_SPACES RE_ANY RE_END
    RE_VARIABLE = RE_BEGIN RE_VAR RE_SET RE_END

    alias = 0
    reset()
    module = 0
}

{
    if (action == "alias") {
        if (match($0, RE_ALIAS, m)) {
            append(m[1])
        } else if (match($0, RE_FUNCTION, m)) {
            n = split(doc, array, "\n")
            for (i = 1; i<= n; i++) {
                print array[i] " = " m[1]
            }
            reset()
        } else {
            reset()
        }
    } else if (action == "doc") {
        # doc
        if (match($0, RE_SHEBANG, m)) {
            append("! " m[1])
        } else if (match($0, RE_DOC, m)) {
            append(m[1])
        } else if (match($0, RE_ALIAS, m)) {
            append("= " m[1])
            if (m[1] == target) {
                alias = 1
            }
        # set
        } else if (match($0, RE_CONSTANT, m)) {
            if (m[1] == target) {
                output(m[1], "constant")
            } else {
                reset()
            }
        } else if (match($0, RE_VARIABLE, m)) {
            if (m[1] == target) {
                output(m[1], "variable")
            } else {
                reset()
            }
        # others
        } else if (match($0, RE_MODULE, m)) {
            reset()
            if (m[1] == target) {
                module = 1
            }
        } else if (match($0, RE_FUNCTION, m)) {
            if (alias) {
                print "= " target
                output(m[1], "function")
            } else if (m[1] == target) {
                output(target, "function")
            } else {
                reset()
            }
        } else {
            if (module) {
                output(target, "module")
            } else {
                reset()
            }
        }
    }
}