add base sketch function to language

src/lang/executor.test.ts

@@ -65,13 +65,13 @@ show(mySketch)
     expect(
       root.mySketch.map(({ previousPath, geo, ...rest }: any) => rest)
     ).toEqual([
-      { type: 'base', from: [0, 0] },
+      { type: 'base', from: [0, 0], sourceRange: [0, 0] },
       { type: 'toPoint', to: [0, 1], sourceRange: [25, 45], name: 'myPath' },
       { type: 'toPoint', to: [1, 1], sourceRange: [48, 59] },
       { type: 'toPoint', to: [1, 0], sourceRange: [67, 90], name: 'rightPath' },
       {
         type: 'close',
-        firstPath: { type: 'base', from: [0, 0] },
+        firstPath: { type: 'base', from: [0, 0], sourceRange: [0, 0] },
         sourceRange: [93, 100],
       },
     ])

src/lang/executor.ts

@@ -76,7 +76,7 @@ export const executor = (
               return _programMemory.root[arg.name]
             }
           })
-          if ('lineTo' === fnName || 'close' === fnName) {
+          if ('lineTo' === fnName || 'close' === fnName || 'base' === fnName) {
             if (options.bodyType !== 'sketch') {
               throw new Error(
                 `Cannot call ${fnName} outside of a sketch declaration`
@@ -108,7 +108,7 @@ export const executor = (
             return _programMemory.root[arg.name]
           }
         })
-        if ('lineTo' === functionName || 'close' === functionName) {
+        if ('lineTo' === functionName || 'close' === functionName || 'base' === functionName) {
           if (options.bodyType !== 'sketch') {
             throw new Error(
               `Cannot call ${functionName} outside of a sketch declaration`

src/lang/sketch.ts

@@ -49,12 +49,14 @@ export type Path =
   | {
       type: 'base'
       from: Coords2d
+      sourceRange: SourceRange
     }
 
 function addBasePath(programMemory: ProgramMemory) {
   const base: Path = {
     type: 'base',
     from: [0, 0],
+    sourceRange: [0, 0],
   }
   if (programMemory._sketch?.length === 0) {
     return {
@@ -90,6 +92,29 @@ function getCoordsFromPaths(paths: Path[], index = 0): Coords2d {
 }
 
 export const sketchFns = {
+  base: (programMemory: ProgramMemory,
+    name: string = '',
+    sourceRange: SourceRange,
+    ...args: any[]
+    ): PathReturn => {
+      if(programMemory._sketch?.length > 0) {
+        throw new Error('Base can only be called once')
+      }
+      const [x, y] = args as [number, number]
+      let from: [number, number] = [x, y]
+      const newPath: Path = {
+        type: 'base',
+        from,
+        sourceRange,
+      }
+      return {
+        programMemory: {
+          ...programMemory,
+          _sketch: [...(programMemory?._sketch || []), newPath],
+        },
+        currentPath: newPath,
+      }
+  },
   close: (
     programMemory: ProgramMemory,
     name: string = '',