Merge pull request #1604 from DanielXMoore/for-join

`for join` reduction to concatenate strings

civet.dev/reference.md

@@ -1936,7 +1936,7 @@ numEven := for count item of array
 numKeys := for count key in object
 </Playground>
 
-`for sum` adds up the body values with `+`.
+`for sum` adds up the body values with `+`, starting from `0`.
 If there is no body, it adds the item being looped over.
 
 <Playground>
@@ -1962,6 +1962,14 @@ min := for min item of array
 max := for max item of array
 </Playground>
 
+`for join` concatenates the body values as strings, using `+`.
+It's like `for sum` but starting from `""` instead of `0`.
+
+<Playground>
+all := for join item of array
+  `[${item.type}] ${item.title}`
+</Playground>
+
 ### Object Comprehensions
 
 Loops can also accumulate their body values into an object.

source/parser.hera

@@ -4767,7 +4767,7 @@ ForStatementControlWithReduction
     return { ...control, reduction }
 
 ForReduction
-  ( "some" / "every" / "count" / "sum" / "product" / "min" / "max" ):subtype NonIdContinue __:ws ->
+  ( "some" / "every" / "count" / "sum" / "product" / "min" / "max" / "join" ):subtype NonIdContinue __:ws ->
     return {
       type: "ForReduction",
       subtype,

source/parser/function.civet

@@ -669,6 +669,7 @@ function iterationDeclaration(statement: IterationStatement | ForStatement)
         when "min" then "Infinity"
         when "max" then "-Infinity"
         when "product" then "1"
+        when "join" then '""'
         else "0"
   else if statement.object
     declaration.children.push "={}"
@@ -696,7 +697,7 @@ function iterationDeclaration(statement: IterationStatement | ForStatement)
               resultsRef, " = false; break}" ]
           when "count"
             [ "if (", node, ") ++", resultsRef ]
-          when "sum" then [ resultsRef, " += ", node ]
+          when "sum", "join" then [ resultsRef, " += ", node ]
           when "product" then [ resultsRef, " *= ", node ]
           when "min" then [ resultsRef, " = Math.min(", resultsRef, ", ", node, ")" ]
           when "max" then [ resultsRef, " = Math.max(", resultsRef, ", ", node, ")" ]

source/parser/types.civet

@@ -416,7 +416,7 @@ export type ForDeclaration
 
 export type ForReduction
   type: "ForReduction"
-  subtype: "some" | "every" | "count" | "sum" | "product" | "min" | "max"
+  subtype: "some" | "every" | "count" | "sum" | "product" | "min" | "max" | "join"
 
 export type SwitchStatement
   type: "SwitchStatement"

test/for.civet

@@ -1282,6 +1282,7 @@ describe "for", ->
       z = for product of y
       z = for min of y
       z = for max of y
+      z = for join of y
       ---
       const results=[];for (const some of y) {results.push(some)};z = results
       const results1=[];for (const every of y) {results1.push(every)};z = results1
@@ -1290,6 +1291,7 @@ describe "for", ->
       const results4=[];for (const product of y) {results4.push(product)};z = results4
       const results5=[];for (const min of y) {results5.push(min)};z = results5
       const results6=[];for (const max of y) {results6.push(max)};z = results6
+      const results7=[];for (const join of y) {results7.push(join)};z = results7
     """
 
     testCase """
@@ -1302,6 +1304,7 @@ describe "for", ->
       z = for product x of y
       z = for min x of y
       z = for max x of y
+      z = for join x of y
       ---
       let results=false;for (const x of y) {results = true; break};z = results
       let results1=true;for (const x of y) {results1 = false; break};z = results1
@@ -1310,6 +1313,7 @@ describe "for", ->
       let results4=1;for (const x of y) {results4 *= x};z = results4
       let results5=Infinity;for (const x of y) {results5 = Math.min(results5, x)};z = results5
       let results6=-Infinity;for (const x of y) {results6 = Math.max(results6, x)};z = results6
+      let results7="";for (const x of y) {results7 += x};z = results7
     """
 
     testCase """
@@ -1329,6 +1333,8 @@ describe "for", ->
         f x
       z = for max x of y
         f x
+      z = for join x of y
+        f x
       ---
       let results=false;for (const x of y) {
         if (f(x)) {results = true; break}
@@ -1351,6 +1357,9 @@ describe "for", ->
       let results6=-Infinity;for (const x of y) {
         results6 = Math.max(results6, f(x))
       };z = results6
+      let results7="";for (const x of y) {
+        results7 += f(x)
+      };z = results7
     """
 
     testCase """
@@ -1363,6 +1372,7 @@ describe "for", ->
       z or for product x of y
       z or for min x of y
       z or for max x of y
+      z or for join x of y
       ---
       z || (()=>{let results=false;for (const x of y) {results = true; break}return results})()
       z || (()=>{let results1=true;for (const x of y) {results1 = false; break}return results1})()
@@ -1371,6 +1381,7 @@ describe "for", ->
       z || (()=>{let results4=1;for (const x of y) {results4 *= x}return results4})()
       z || (()=>{let results5=Infinity;for (const x of y) {results5 = Math.min(results5, x)}return results5})()
       z || (()=>{let results6=-Infinity;for (const x of y) {results6 = Math.max(results6, x)}return results6})()
+      z || (()=>{let results7="";for (const x of y) {results7 += x}return results7})()
     """
 
     testCase """
@@ -1383,6 +1394,7 @@ describe "for", ->
       for product x of y
       for min x of y
       for max x of y
+      for join x of y
       ---
       let results=false;for (const x of y) {results = true; break}results
       let results1=true;for (const x of y) {results1 = false; break}results1
@@ -1391,6 +1403,7 @@ describe "for", ->
       let results4=1;for (const x of y) {results4 *= x}results4
       let results5=Infinity;for (const x of y) {results5 = Math.min(results5, x)}results5
       let results6=-Infinity;for (const x of y) {results6 = Math.max(results6, x)}results6
+      let results7="";for (const x of y) {results7 += x}results7
     """
 
     testCase """
@@ -1403,14 +1416,16 @@ describe "for", ->
       => for product x of y
       => for min x of y
       => for max x of y
+      => for join x of y
       ---
       () => { let results=false;for (const x of y) {results = true; break};return results; };
       () => { let results1=true;for (const x of y) {results1 = false; break};return results1; };
       () => { let results2=0;for (const x of y) {++results2};return results2; };
       () => { let results3=0;for (const x of y) {results3 += x};return results3; };
       () => { let results4=1;for (const x of y) {results4 *= x};return results4; };
       () => { let results5=Infinity;for (const x of y) {results5 = Math.min(results5, x)};return results5; };
-      () => { let results6=-Infinity;for (const x of y) {results6 = Math.max(results6, x)};return results6; }
+      () => { let results6=-Infinity;for (const x of y) {results6 = Math.max(results6, x)};return results6; };
+      () => { let results7="";for (const x of y) {results7 += x};return results7; }
     """
 
     testCase """
@@ -1423,6 +1438,7 @@ describe "for", ->
       e := x for product x of y
       f := x for min x of y
       g := x for max x of y
+      h := x for join x of y
       ---
       const a =(()=>{let results=false;for (const x of y) { if ( x) {results = true; break} }return results})()
       const b =(()=>{let results1=true;for (const x of y) { if (! x) {results1 = false; break} }return results1})()
@@ -1431,6 +1447,7 @@ describe "for", ->
       const e =(()=>{let results4=1;for (const x of y) { results4 *=  x }return results4})()
       const f =(()=>{let results5=Infinity;for (const x of y) { results5 = Math.min(results5,  x) }return results5})()
       const g =(()=>{let results6=-Infinity;for (const x of y) { results6 = Math.max(results6,  x) }return results6})()
+      const h =(()=>{let results7="";for (const x of y) { results7 +=  x }return results7})()
     """
 
     testCase """