There are a few rules relevant to your situation here. The first is one of the ones for activated abilities in general:
602.2. To activate an ability is to put it onto the stack and pay its costs, so that it will eventually resolve and have its effect. Only an object's controller (or its owner, if it doesn't have a controller) can activate its activated ability unless the object specifically says otherwise. Activating an ability follows the steps listed below, in order. If, at any point during the activation of an ability, a player is unable to comply with any of those steps, the activation is illegal; the game returns to the moment before that ability started to be activated (see rule 721, "Handling Illegal Actions"). Announcements and payments can't be altered after they've been made.
Next are the rules for loyalty abilities:
606.1. Some activated abilities are loyalty abilities, which are subject to special rules.
606.2. An activated ability with a loyalty symbol in its cost is a loyalty ability. Normally, only planeswalkers have loyalty abilities.
606.3. A player may activate a loyalty ability of a permanent they control any time they have priority and the stack is empty during a main phase of their turn, but only if no player has previously activated a loyalty ability of that permanent that turn.
When taken together, this means a clause on who can activate an ability will apply if that clause is put at the end of the loyalty ability. This means that your loyalty ability works.
Keep in mind, however, that other restrictions for activating a loyalty ability will apply. Assuming no external effects, this means the ability can only be activated at sorcery speed; and if a player has already activated a loyalty ability of the relevant planeswalker in the turn, no more can be activated for that turn.
Note that rules-wise, giving an object changeling doesn't actually give all creature types to that object. This is because type-changing effects are processed in an earlier layer than ability-adding effects are. By the time the object gains changeling, there won't be a layer further down that will apply the creature types that changeling gives. Because of this, "[objects] have changeling" needs to be "[objects] have all creature types" (with "and have changeling" added if you care specifically about the ability being present).
Uplift (Common) 2W
Sorcery
Target creature gets +2/+2 and gains flying until end of turn.
Foretell W(As you draw this card, you may reveal it and pay W.)
When this card is foretold, target creature gets +1/+1 and gains flying until end of turn.
There is a huge problem with the mechanic as currently written: If an ability of an object would trigger, but the object's identity isn't known to all players at that time, it doesn't trigger.
603.2e. If a triggered ability's trigger condition is met, but the object with that triggered ability is at no time visible to all players, the ability does not trigger.
An ability that reads "When you draw this card, ..." necessarily triggers from the hand, a zone that (usually) contains cards whose identity is only known to the player who owns the cards in it. Because of this, such an ability will never trigger. It doesn't matter that the card is revealed upon resolution, because an ability can't resolve if it never triggers.
Therefore, it is impossible for forebode to be an ability word in this state. You must change some part of the mechanic, or make it a keyword ability, in order for it to work.
Assuming that by "Type cards in your graveyard", you actually mean "[type] cards in your graveyard", where [type] can be substituted for any card type in the game, then yes, that is the best wording you can get for your desired effect.
I really wonder if the rules could be translated into a sort of programming language well enough for new players to understand it.
Regardless of whatever programming language or pseudo-programming language you pick, there will always be players who don't understand the language you use. It is objectively better to just use a natural language, as the number of people who would benefit from Magic syntax being a programming language is less than the number of people who are affected by the grammatical ambiguity provided by their natural language.
Magic is Magic in part because of its color pie restrictions. To say that certain effects need to be more universal to "balance the game engine" and designing cards as such means that you're no longer designing custom Magic cards, as you've practically thrown an entire founding facet of the game out the window. You're instead designing your own game with your own flavor rules, that happen to use Magic's rule set. And that doesn't make for a good Magic card designer.
Your platitudes don't really mean much on this forum. While the rest of us here are content with fitting our designs within Magic's design restrictions, you don't think doing so is fun. That's fine. But you don't then get to also say that we should ditch Magic's color pie aspect and make cards in a way you are attempting to.
Peace Turtle unfortunately doesn't work. The way layers work, the game will first look at the printed power and toughness of the relevant creature, if any, then give and remove abilities as appropriate, and then apply power and toughness modifiers. Because of this, a creature with printed power 4 or less will never have defender with Peace Turtle's ability, even if there are counters or buffs that increase its power to 5 or greater. Similarly, a creature with printed power 5 or greater will always have defender with Peace Turtle's ability, even if there are counters or debuffs that lower its power to 4 or less.
To get around this, you need to either use a state-triggered ability, or an activated ability, such as the following:
When a creature's power becomes 5 or greater, if it doesn't have defender, it gains defender until end of turn.
0: Target creature with power 5 or greater gains defender until end of turn.
There are obvious advantages and disadvantages to using both, but you can't use a static ability to accomplish what you want, I'm afraid.
Absolutely untrue. If a player is forced to cast a spell, and the conditions for being able to do so are present (untapped mana resources), then the order of operations for doing that is a given for the effect.
You don't get to make this claim if you don't know the game's rules.
That's exactly what the rulings would say for this card.
Rulings aren't rules. You're confusing the two. The fact that you are means you don't have sufficient rules knowledge to be talking about the rules the way you are.
Familiarize yourself with the rules more and then you'll be treated more seriously on your rules claims. Right now, all your rules-related claims are complete jokes.
You need reminder text on your card. If a person who knows the ins and outs of Magic's rules reads your card and has absolutely no idea what your card does, your card is worded badly. If you disagree, you are wrong.
You seem to be missing the point here, in that this statement had nothing to do with how I feel personally feel about errata, but relates to the fact that we already have a catalog of printed cards that, "change the 'text' of target spell or permanent", and critically rely on errata to define what the term 'text' specifically means (referring to only what's in the "text box" itself).
There does not exist a "hack" card with errata that clarifies what the word "text" is. You're not using the term errata correctly.
Not sure what you mean by "rigorous mathematical definition".
This is not a matter of mathematics, it's a matter of English.
It's a matter of mathematics because the English definition of the terms you're trying to use here refer to the mathematical definitions of those terms.
I never said that the issue was with the word "closest", so I'm not sure why you chose to focus on that.
It's perfectly fine that way, and I don't see how this is any different, or less acceptable than that. It's even a little less ambiguous, as the term "matching even or odd" and "integer" gives clue to specifics.
It's only perfectly fine to you. The problem is that it's not perfectly fine in Magic wording, and you keep thinking that whatever is fine for you is the same as whatever is fine for Magic wording. It's not.
You keep citing mathematical definitions of words in your argument. That's fine, but just because there is a commonly associated English antonym for a mathematical term, it doesn't mean the antonym doesn't need to be defined. "Irrational number," the associated English antonym for "rational number," doesn't automatically get a definition just because "rational number" does. "Irrational number" doesn't have a definition without being defined explicitly as what it is.
Similarly, "matching numbers" doesn't have a definition just because "opposite numbers" does. You need to explicitly state what criteria about the numbers constitute "matching" on the card. The bolded wording you provided in response to saneatali works here, as far as parity is concerned.
Like a mana symbol, the term '+1/+1—or +1/+1 counter' is technically a "value", where the number symbol serves as an "identifier". However, unlike a mana symbol, since an actual number symbol (in plain text) is used here, it's at the discretion of developer to allow the effect to change the 'number symbol' of the 'text'. I did explain this in the opening post, that I was uncertain as to what combination of number words or number symbols this should be able to change. A colorless mana symbol might have a 'number symbol' or 'text' within it, but it's encased within an image, which totally separates it from a traditional number symbol or text.
Even with the number symbol within it, a colorless mana symbol is a symbol of its own, and needs to be identified individually (as a mana symbol) to be changeable. That's not the case here with number symbols that identify power/toughness altering counters. It's plain text, that technically moreso, should be viable for change with this effect.
A numeral appearing in plain text isn't sufficient for it to be changed the way you mention, just as a color word appearing in plain text isn't sufficient for it to be changed by color word-changing effects.
I would also question how viable the wording composure is for, "increase or decrease a number by 2" even is. That's like‒super-way out of the ballpark for MTG. This is the most function way to fit the effect within the confines of MTG wording composure. The word "matching" isn't really a stretch by any logical means, imo. I don't even recall a card using that term. Let me look it up. Nope, the gatherer doesn't even come up with anything, so I think it's fair to say that the context is open to interpretation.
Your wording is even more confusing than "increase or decrease a number by 2." "Closest matching even or odd integer" has absolutely no rigorous mathematical definition. The entire point of Magic wording is so that the context isn't ambiguous and up for interpretation, so the fact that you advertise your wording as such means your wording is bad.
To address the +1/+1 counter question. Yes, it could change a +1/+1 counter to a +3/+3 counter.
No, this is incorrect. +1/+1 and -1/-1 are descriptors for a kind of counter, and can only be be treated as a singular unit. Just because they have numerals in the descriptor doesn't mean those numerals are automatically eligible to be changed.
"Whenever ~ attacks, you may have it phase out instead...."
This doesn't work. "Whenever" denotes a triggered ability, and "instead" denotes a replacement effect. They are mutually exclusive.
Normally, the proper wording would be to replace "Whenever" with "If". However, since attacking with a creature is a turn-based action that involves following a sequence of smaller actions, the turn-based action cannot itself be a replaced event of a replacement effect.
"During your next combat phase, ..."
This isn't specific enough. You need to specify which step of the combat phase you're referring to.
The way I've composed the effect, with "As this enters the battlefield", the card would count the number of lands you control while it's on the stack (before it comes into play) to decide if it inherits the mana ramp bonus or not.
Lands don't use the stack.
It's also essential to the functionality to do it this way, as by opening up that interactivity with the charge counter, it makes the card more open to cheap exploits, which can detract from the aspects of challenge implemented here (to provide the central basis for fun in the game). The hard-coded functionality also intends to provide boundaries and restrictions, that must be entirely locked-off from exploit, for balance of the game (by preventing the aspects of challenge/boundaries/restrictions from being too cheaply bi-passed or hot-fixed).
A charge counter is used for memory aid purposes, not for intentionally designing the card to be synergistic with other cards that care about charge counters. The memory aid is more important than the increased interactivity here. You can use whatever kind of counter you want, not just charge counters. The important thing is that some kind of counter is there for players to be able to remember the special effect.
Next are the rules for loyalty abilities:
606.2. An activated ability with a loyalty symbol in its cost is a loyalty ability. Normally, only planeswalkers have loyalty abilities.
606.3. A player may activate a loyalty ability of a permanent they control any time they have priority and the stack is empty during a main phase of their turn, but only if no player has previously activated a loyalty ability of that permanent that turn.
When taken together, this means a clause on who can activate an ability will apply if that clause is put at the end of the loyalty ability. This means that your loyalty ability works.
Keep in mind, however, that other restrictions for activating a loyalty ability will apply. Assuming no external effects, this means the ability can only be activated at sorcery speed; and if a player has already activated a loyalty ability of the relevant planeswalker in the turn, no more can be activated for that turn.
Yes, that works just fine.
An ability that reads "When you draw this card, ..." necessarily triggers from the hand, a zone that (usually) contains cards whose identity is only known to the player who owns the cards in it. Because of this, such an ability will never trigger. It doesn't matter that the card is revealed upon resolution, because an ability can't resolve if it never triggers.
Therefore, it is impossible for forebode to be an ability word in this state. You must change some part of the mechanic, or make it a keyword ability, in order for it to work.
Regardless of whatever programming language or pseudo-programming language you pick, there will always be players who don't understand the language you use. It is objectively better to just use a natural language, as the number of people who would benefit from Magic syntax being a programming language is less than the number of people who are affected by the grammatical ambiguity provided by their natural language.
Your platitudes don't really mean much on this forum. While the rest of us here are content with fitting our designs within Magic's design restrictions, you don't think doing so is fun. That's fine. But you don't then get to also say that we should ditch Magic's color pie aspect and make cards in a way you are attempting to.
To get around this, you need to either use a state-triggered ability, or an activated ability, such as the following:
There are obvious advantages and disadvantages to using both, but you can't use a static ability to accomplish what you want, I'm afraid.
You don't get to make this claim if you don't know the game's rules.
Rulings aren't rules. You're confusing the two. The fact that you are means you don't have sufficient rules knowledge to be talking about the rules the way you are.
Familiarize yourself with the rules more and then you'll be treated more seriously on your rules claims. Right now, all your rules-related claims are complete jokes.
There does not exist a "hack" card with errata that clarifies what the word "text" is. You're not using the term errata correctly.
It's a matter of mathematics because the English definition of the terms you're trying to use here refer to the mathematical definitions of those terms.
I never said that the issue was with the word "closest", so I'm not sure why you chose to focus on that.
It's only perfectly fine to you. The problem is that it's not perfectly fine in Magic wording, and you keep thinking that whatever is fine for you is the same as whatever is fine for Magic wording. It's not.
You keep citing mathematical definitions of words in your argument. That's fine, but just because there is a commonly associated English antonym for a mathematical term, it doesn't mean the antonym doesn't need to be defined. "Irrational number," the associated English antonym for "rational number," doesn't automatically get a definition just because "rational number" does. "Irrational number" doesn't have a definition without being defined explicitly as what it is.
Similarly, "matching numbers" doesn't have a definition just because "opposite numbers" does. You need to explicitly state what criteria about the numbers constitute "matching" on the card. The bolded wording you provided in response to saneatali works here, as far as parity is concerned.
A numeral appearing in plain text isn't sufficient for it to be changed the way you mention, just as a color word appearing in plain text isn't sufficient for it to be changed by color word-changing effects.
Your wording is even more confusing than "increase or decrease a number by 2." "Closest matching even or odd integer" has absolutely no rigorous mathematical definition. The entire point of Magic wording is so that the context isn't ambiguous and up for interpretation, so the fact that you advertise your wording as such means your wording is bad.
No, this is incorrect. +1/+1 and -1/-1 are descriptors for a kind of counter, and can only be be treated as a singular unit. Just because they have numerals in the descriptor doesn't mean those numerals are automatically eligible to be changed.
This doesn't work. "Whenever" denotes a triggered ability, and "instead" denotes a replacement effect. They are mutually exclusive.
Normally, the proper wording would be to replace "Whenever" with "If". However, since attacking with a creature is a turn-based action that involves following a sequence of smaller actions, the turn-based action cannot itself be a replaced event of a replacement effect.
This isn't specific enough. You need to specify which step of the combat phase you're referring to.
Lands don't use the stack.
A charge counter is used for memory aid purposes, not for intentionally designing the card to be synergistic with other cards that care about charge counters. The memory aid is more important than the increased interactivity here. You can use whatever kind of counter you want, not just charge counters. The important thing is that some kind of counter is there for players to be able to remember the special effect.
A creature's toughness being at 0 or less doesn't cause that creature to be destroyed.