Find the intersection of two lines: Difference between revisions

=={{header|Lambdatalk}}==

{{trans|Python}}

<syntaxhighlight lang="scheme">

{def line_intersect

{def line_intersect.sub

{lambda {:111 :121 :112 :122 :211 :221 :212 :222}

{let { {:x :111} {:y :121}

{:z {- {* {- :222 :221} {- :112 :111}}

{* {- :212 :211} {- :122 :121}} } }

{:a {- :112 :111}} {:b {- :122 :121}}

{:c {- :212 :211}} {:d {- :222 :221}}

{:e {- :121 :221}} {:f {- :111 :211}}

{:g {- :121 :211}} {:h {- :122 :121}}

} {if {> :z 0}

then {A.new ∞ ∞}

else {let { {:x :x} {:y :y} {:a :a} {:b :b}

{:t1 {/ {- {* :c :e} {* :d :f}} :z} }

{:t2 {/ {- {* :a :g} {* :h :f}} :z} }

} {if {and {>= :t1 0} {<= :t1 1} {>= :t2 0} {<= :t2 1}}

then {A.new {+ :x {* :t1 :a}} {+ :y {* :t1 :b}} }

else {A.new ∞ ∞}} }}}}}

{lambda {:1 :2}

{line_intersect.sub

{A.first {A.first :1}} {A.last {A.first :1}}

{A.first {A.last :1}} {A.last {A.last :1}}

{A.first {A.first :2}} {A.last {A.first :2}}

{A.first {A.last :2}} {A.last {A.last :2}} }}}

-> line_intersect

{line_intersect {A.new {A.new 4 0} {A.new 6 10}}

{A.new {A.new 0 3} {A.new 10 7}}}

-> [5,5]

{line_intersect {A.new {A.new 4 0} {A.new 6 10}}

{A.new {A.new 0 3} {A.new 10 7.1}}}

-> [5.010893246187364,5.05446623093682]

{line_intersect {A.new {A.new 1 -1} {A.new 4 4}}

{A.new {A.new 2 5} {A.new 3 -2}}}

-> [2.5,1.5]

{line_intersect {A.new {A.new 0 0} {A.new 0 0}}

{A.new {A.new 0 3} {A.new 10 7}}}

-> [∞,∞]

{line_intersect {A.new {A.new 0 0} {A.new 1 1}}

{A.new {A.new 1 2} {A.new 4 5}}}

-> [∞,∞]

</syntaxhighlight>