[match:factor]
M1: "-2"
M2: "+22"
M3: "-2.71828"
M4: "-x"
M5: "(2 + x)"
M6: "-(a * b)"
M7: "-5e(2+sin(x))(a-b)(c/d)i"

[fail:factor]
F1: "x4"
F2: "- 2"


[match:tail]
M1: "x(2+3)"
M2: "xyz"
M3: "a"
M4: "x"
M5: "x(-y)"
M6: "x^5y"

[ast:tail]

[fail:tail]
F1: "5x"
F2: "xia"
F3: "x-y"


[match:seq]
M1: "xy"
M2: "xesin(y)(a+b)"

[ast:seq]

[fail:seq]
F1: "a"
F2: "-xz"


[match:sign]
M1: "-"
M2: "+"

[ast:sign]

[fail:sign]