namespace algebra.equations

supports algebra.equations.linear

# -------------------------------------------------------------
# Feedback

feedback same = @ok
feedback noteq = @incorrect
feedback unknown = @ok
feedback ok = {Well done!}
feedback buggy = {@incorrect @recognized}
feedback detour = @ok

feedback hint = hint
feedback step = Use @expected to rewrite the equation into: @after

string incorrect = {This step is incorrect.}

# -------------------------------------------------------------
# Rules

text coverup.negate = {rule negate}
text coverup.onevar.minus-left = {rule minus left}
text coverup.onevar.minus-right = {rule minus right}
text coverup.onevar.plus = {rule plus}
text coverup.times = {rule times}
text linear.distr-times = distribution multiplication
text linear.flip = flip equation
text linear.merge = merge similar terms
text linear.norm-mixed = normalize mixed fraction
text linear.norm-rational = normalize rational number
text linear.remove-div = remove division
text linear.var-left = variable to left

# -------------------------------------------------------------
# Buggy rules

text buggy.cancel-minus = Cancel terms on both sides, but terms have different signs.
text buggy.distr-times-denom = Incorrect distribution of times over plus: one of the terms is a fraction, and the outer expression is multiplied by the fraction's denominator.
text buggy.distr-times-plus = Distribution of times over plus: one term is not multiplied.
text buggy.distr-times-plus-forget = Incorrect distribution of times over plus: one term is forgotten.
text buggy.distr-times-plus-sign = Incorrect distribution of times over plus: changing sign of addition.
text buggy.distr-times-too-many = Strange distribution of times over plus: a*(b+c)+d, where 'a' is also multiplied to d.
text buggy.divide-negate = Dividing, but wrong sign.
text buggy.divide-numdenom = Dividing both sides, but swapping numerator/denominator.
text buggy.flip-negate-one-side = Negate terms on one side only.
text buggy.minus-minus = Incorrect rewriting of a-(b-c): forgetting to change sign.
text buggy.multiply-forget-one = Multiply the terms on both sides of the equation, but forget one.
text buggy.multiply-one-side = Multiplication on one side of the equation only
text buggy.negate-all = Negating all terms (on both sides of the equation, but forgetting one term.
text buggy.negate-one-side = Negate terms on one side only.
text buggy.plus = Moving a term from the left-hand side to the right-hand side (or the other way around), but forgetting to change the sign.
text buggy.priority-times = Prioity of operators is changed, possibly by ignoring some parentheses.